Not least because I need a lie down after trying to keep up with those changes at the top.
Fear not, we'll be back with you tomorrow to bring you the final round from Colonial Country Club, when we'll find out who wins the first tournament on golf's return.
And here is Rory McIlroy: "A little scrappy. I birdied the two par fives, there were a couple of loose iron shots at the seventh and eighth which cost me bogeys.
"I didn't think I played well today but looking at the leaderboard no one else pulled away. I'm within striking distance."
Post update
And breathe...
What got into everyone down that back nine?! At one point we had a six-way tie at the top.
Xander Schauffele sits alone in the lead at 13 under par, but just one back is a five-strong gang of Jordan Spieth, Justin Thomas, Brandon Grace, Collin Morikawa and Gary Woodland.
In fact, there are 13 players within three shots of Schauffele, including world number one Rory McIlroy, 2018 Masters champion Patrick Reed and former US Open winner Justin Rose.
Good luck picking a winner from that bunch.
Spieth goes close at 18
Spieth -12, Varner III -11 (F)
Oh, so close from Jordan Spieth!
That would have given him a share of the lead heading into the final day.
The three-time major winner left his approach short of the green but clipped on almost to perfection. He groans as it wriggles off target, and taps in from an inch or so for par.
Spieth remains at 12 under par, with Harold Varner III closing out in par to stay one further back.
Morikawa misses birdie chance on last
Morikawa -12, DeChambeau -10 (F)
Collin Morikawa is on the 18th green in two. A mid-range birdie putt for the 23-year-old to take him back into a share of the lead.
He starts it left and wills it right, but it doesn't break quickly enough and the American taps in for par. Fantastic round. He's 64 67 67 for the week so far. Sitting at 12 under par.
Bryson DeChambeau made an eagle at 11 but failed to gain shots elsewhere. He finishes today at 10 under par - just three off the lead.
Post update
Spieth -12, Varner III -11 (17)
Jordan Spieth hasn't made a birdie on the back nine. He can't stop that streak at 17 either. A little shake of the head as he walks away with another par having dived into a bunker with his approach.
Harold Varner III would love a birdie to take him into that group one off the lead at 12 under. A great chance here from within five feet, but it loops around the cup and stays up. Harsh.
Schauffele takes outright lead
Schauffele -13, McIlroy -10 (F)
Anyone else want in on top spot?!
It's like a Colonial Country Club pizza, there's a slice for everyone... who's going to be that kid at the all-you-can eat buffet that chows down every slice in sight and is first in the ice cream queue.
Could it be Xander Schauffele? Twelve feet for a birdie at the last. Nails it. Lovely putt. He takes all of the pizza! For now...
World number one Rory McIlroy is also home. A round of 69 today to leave him at 10 under par. Still right in the mix, despite the back to back bogeys on the front nine.
Morikawa in share of lead
DeChambeau -10, Morikawa -12 (17)
Bryson DeChambeau has a 21-foot birdie putt on the 17th green. Sink this and he's in a six-way tie for the lead on -12.
Whoa ball. He steams that a good six feet past the hole. And that's a three-putt bogey.
But his playing partner Collin Morikawa is going the other way. A birdie on 17 propels him to the top of the pops and we do have six in the lead!
Post update
Spieth -12, Varner III -11 (16)
It's not dropping for Harold Varner III today. He's had a fantastic week so far and has played well today too, just not had the breaks. A birdie putt at the par-three 16th flirts with the cup but doesn't commit.
Jordan Spieth stings his tee shot to within 10 feet but two putts for par.
Woodland makes it five at the top
Woodland -12 (F)
Make that five at the top...
Gary Woodland, the US Open champion, joins the party with a birdie-birdie finish.
This is going to be some final day tomorrow.
Poor finish for Rose
Rose -10 (F)
Justin Rose is scratching his head as he departs the 18th green.
It's a bogey-par-bogey finish for the Englishman.
He found a greenside bunker with his second to the last but had an awkward stance with one foot in, one foot out. He squirted the ball out to about eight feet but missed the par putt. Disappointing.
Post update
Schauffele -12, McIlroy (17)
Big chance for Xander Schauffele to scratch off that bogey at the last and take the outright lead.
Around 10 feet to play with on the 17th, picks his line and looks to be good but wriggles left.
As you were.
Four-way tie for lead after Spieth bogey
Spieth -12, Varner III -11 (15)
Uh oh. Jordan Spieth cracked his drive 331 yards but it's the remaining 80 that have caused him problems. He's left with a 10-foot putt to save par. It kisses the cup, but stays up.
Spieth bogeys and now we have a four-way tie - that dropped shot brings Justin Thomas, Branden Grace and Xander Schauffele into ta share of top spot.
Thomas one off the lead
Thomas -12, Grace -12 (17)
South Africa's Branden Grace and American Justin Thomas have both got short birdie putts on the 17th.
Grace first and he's moving to -12. Thomas has a tiddler. And he turns and raises his ball to acknowledge the non-existent cheers. He's at -12 too.
This leaderboard is congested with some of the world's finest.
Bogey for Schauffele
Schauffele -12, McIlroy -10 (16)
Jordan Spieth is chewing Harold Varner III's ear off with a tale or two as they march down the 15th fairway. He doesn't know it yet, but he's just retaken the outright lead.
Xander Schauffele, on the par-three 16th, leaves his tee shot right and then duffs a chip from the fringes to leave him a long, speedy par putt. He needs two to convert.
Bogey for the American. Back to 12 under, one off the lead.
Bogey for Varner III
Spieth -13, Varner III -11 (14)
First blemish on Harold Varner III's card today. It's a bogey at the par-four 14th. The American finds a bunker guarding the green with his approach and clips out to 15 feet. But he needs two putts to clear it up.
Jordan Spieth polishes off his fifth par since the turn.
Another birdie slides by
Rose -11 (17)
Justin Rose gives himself a chance to avenge that dropped shot on the 16th with another pin-seeker on the 17th. He's left himself a putt of about a dozen feet or so.
The radar is a little awry right now. Six inches left of the hole. A par. One to play.
Trivia time
#bbcgolf
Since 1948 only seven non-Americans have been named either PGA or PGA tour Player of the Year. Can you name them? #bbcgolf
Your answers are flying in...
Mark Swain: Nick Faldo. Ernie Els.
Snookered: McIlroy, Donald, Vijay Singh, Faldo, Norman, Harrington.
Torn between Schwartzel and Nick Price for the last one. Errrrrrr Nick Price?
Christopher J Hand: Gary Player, Seve Ballesteros, Greg Norman, Nick Price, Ernie Els, Vijay Singh, Rory McIlroy
Schauffele moves level at the top
Schauffele -13, McIlroy -10 (15)
Schauffele into a share of the lead!
A huge drive takes him to within just 79 yards of the pin and the American wedges on. His putter's sizzling this week and Xander Schauffele eats up the 16 feet to drown his fifth birdie of the day and move alongside Jordan Spieth at 13 under par.
The makeshift grandstand constructed at a hotel behind the course love it.
Live Reporting
Alex Bysouth and Peter Scrivener
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Latest PostUntil tomorrow...
And that's all from us this evening.
Not least because I need a lie down after trying to keep up with those changes at the top.
Fear not, we'll be back with you tomorrow to bring you the final round from Colonial Country Club, when we'll find out who wins the first tournament on golf's return.
Catch you then...
Post update
Rose -10 (F)
McIlroy 'within striking distance' of leaders
McIlroy -10 (F)
And here is Rory McIlroy: "A little scrappy. I birdied the two par fives, there were a couple of loose iron shots at the seventh and eighth which cost me bogeys.
"I didn't think I played well today but looking at the leaderboard no one else pulled away. I'm within striking distance."
Post update
And breathe...
What got into everyone down that back nine?! At one point we had a six-way tie at the top.
Xander Schauffele sits alone in the lead at 13 under par, but just one back is a five-strong gang of Jordan Spieth, Justin Thomas, Brandon Grace, Collin Morikawa and Gary Woodland.
In fact, there are 13 players within three shots of Schauffele, including world number one Rory McIlroy, 2018 Masters champion Patrick Reed and former US Open winner Justin Rose.
Good luck picking a winner from that bunch.
Spieth goes close at 18
Spieth -12, Varner III -11 (F)
Oh, so close from Jordan Spieth!
That would have given him a share of the lead heading into the final day.
The three-time major winner left his approach short of the green but clipped on almost to perfection. He groans as it wriggles off target, and taps in from an inch or so for par.
Spieth remains at 12 under par, with Harold Varner III closing out in par to stay one further back.
Morikawa misses birdie chance on last
Morikawa -12, DeChambeau -10 (F)
Collin Morikawa is on the 18th green in two. A mid-range birdie putt for the 23-year-old to take him back into a share of the lead.
He starts it left and wills it right, but it doesn't break quickly enough and the American taps in for par. Fantastic round. He's 64 67 67 for the week so far. Sitting at 12 under par.
Bryson DeChambeau made an eagle at 11 but failed to gain shots elsewhere. He finishes today at 10 under par - just three off the lead.
Post update
Spieth -12, Varner III -11 (17)
Jordan Spieth hasn't made a birdie on the back nine. He can't stop that streak at 17 either. A little shake of the head as he walks away with another par having dived into a bunker with his approach.
Harold Varner III would love a birdie to take him into that group one off the lead at 12 under. A great chance here from within five feet, but it loops around the cup and stays up. Harsh.
Schauffele takes outright lead
Schauffele -13, McIlroy -10 (F)
Anyone else want in on top spot?!
It's like a Colonial Country Club pizza, there's a slice for everyone... who's going to be that kid at the all-you-can eat buffet that chows down every slice in sight and is first in the ice cream queue.
Could it be Xander Schauffele? Twelve feet for a birdie at the last. Nails it. Lovely putt. He takes all of the pizza! For now...
World number one Rory McIlroy is also home. A round of 69 today to leave him at 10 under par. Still right in the mix, despite the back to back bogeys on the front nine.
Morikawa in share of lead
DeChambeau -10, Morikawa -12 (17)
Bryson DeChambeau has a 21-foot birdie putt on the 17th green. Sink this and he's in a six-way tie for the lead on -12.
Whoa ball. He steams that a good six feet past the hole. And that's a three-putt bogey.
But his playing partner Collin Morikawa is going the other way. A birdie on 17 propels him to the top of the pops and we do have six in the lead!
Post update
Spieth -12, Varner III -11 (16)
It's not dropping for Harold Varner III today. He's had a fantastic week so far and has played well today too, just not had the breaks. A birdie putt at the par-three 16th flirts with the cup but doesn't commit.
Jordan Spieth stings his tee shot to within 10 feet but two putts for par.
Woodland makes it five at the top
Woodland -12 (F)
Make that five at the top...
Gary Woodland, the US Open champion, joins the party with a birdie-birdie finish.
This is going to be some final day tomorrow.
Poor finish for Rose
Rose -10 (F)
Justin Rose is scratching his head as he departs the 18th green.
It's a bogey-par-bogey finish for the Englishman.
He found a greenside bunker with his second to the last but had an awkward stance with one foot in, one foot out. He squirted the ball out to about eight feet but missed the par putt. Disappointing.
Post update
Schauffele -12, McIlroy (17)
Big chance for Xander Schauffele to scratch off that bogey at the last and take the outright lead.
Around 10 feet to play with on the 17th, picks his line and looks to be good but wriggles left.
As you were.
Four-way tie for lead after Spieth bogey
Spieth -12, Varner III -11 (15)
Uh oh. Jordan Spieth cracked his drive 331 yards but it's the remaining 80 that have caused him problems. He's left with a 10-foot putt to save par. It kisses the cup, but stays up.
Spieth bogeys and now we have a four-way tie - that dropped shot brings Justin Thomas, Branden Grace and Xander Schauffele into ta share of top spot.
Thomas one off the lead
Thomas -12, Grace -12 (17)
South Africa's Branden Grace and American Justin Thomas have both got short birdie putts on the 17th.
Grace first and he's moving to -12. Thomas has a tiddler. And he turns and raises his ball to acknowledge the non-existent cheers. He's at -12 too.
This leaderboard is congested with some of the world's finest.
Bogey for Schauffele
Schauffele -12, McIlroy -10 (16)
Jordan Spieth is chewing Harold Varner III's ear off with a tale or two as they march down the 15th fairway. He doesn't know it yet, but he's just retaken the outright lead.
Xander Schauffele, on the par-three 16th, leaves his tee shot right and then duffs a chip from the fringes to leave him a long, speedy par putt. He needs two to convert.
Bogey for the American. Back to 12 under, one off the lead.
Bogey for Varner III
Spieth -13, Varner III -11 (14)
First blemish on Harold Varner III's card today. It's a bogey at the par-four 14th. The American finds a bunker guarding the green with his approach and clips out to 15 feet. But he needs two putts to clear it up.
Jordan Spieth polishes off his fifth par since the turn.
Another birdie slides by
Rose -11 (17)
Justin Rose gives himself a chance to avenge that dropped shot on the 16th with another pin-seeker on the 17th. He's left himself a putt of about a dozen feet or so.
The radar is a little awry right now. Six inches left of the hole. A par. One to play.
Trivia time
#bbcgolf
Since 1948 only seven non-Americans have been named either PGA or PGA tour Player of the Year. Can you name them? #bbcgolf
Your answers are flying in...
Mark Swain: Nick Faldo. Ernie Els.
Snookered: McIlroy, Donald, Vijay Singh, Faldo, Norman, Harrington. Torn between Schwartzel and Nick Price for the last one. Errrrrrr Nick Price?
Christopher J Hand: Gary Player, Seve Ballesteros, Greg Norman, Nick Price, Ernie Els, Vijay Singh, Rory McIlroy
Schauffele moves level at the top
Schauffele -13, McIlroy -10 (15)
Schauffele into a share of the lead!
A huge drive takes him to within just 79 yards of the pin and the American wedges on. His putter's sizzling this week and Xander Schauffele eats up the 16 feet to drown his fifth birdie of the day and move alongside Jordan Spieth at 13 under par.
The makeshift grandstand constructed at a hotel behind the course love it.
Below is his par-saver from earlier...