Tour Championship: Xander Schauffele wins as Justin Thomas claims FedEx Cup
|Tour Championship final-round leaderboard|
|-12 X Schauffele (US); -11 J Thomas (US); -10 R Henley (US), K Kisner (US); -9 Casey (Eng)|
|Selected others: -7 J Speith (US), J Rahm (Spa); -6 S Garcia (Spa), J Rose (Eng); -2 D Johnson (US)|
American Justin Thomas lifted the FedEx Cup as Xander Schauffele became the first rookie to win the season-ending Tour Championship in Atlanta.
Compatriot Xander carded a two-under 68 to finish 12 under par and win by one shot from Thomas, who finished on 66.
England's Paul Casey led by two overnight and was in a strong position to claim the $10m (£7.4m) cup bonus.
However, the 40-year-old had three bogeys on the front nine, his eventual 73 leaving him in fifth on nine under.
Casey, who has not won a PGA Tour title since 2009, had opened the tournament with rounds of 66, 67 and 65 but faded to finish 10th in the FedEx Cup standings.
The competition is the PGA Tour's season-long points race.
Open champion Jordan Spieth led the standings at the start of the week and a seven-under-par finish in Atlanta in tied seventh left the American 660 points behind Thomas in second place overall.
Thomas, 24, has won five times on the PGA Tour this season, including securing his first major at the US PGA Championship last month.
Any of the 30 players in the field theoretically had a chance of the $10m (£7.4m) payout, but only the top five in the standings were assured of doing so by claiming the $1.53m (£1.12m) first prize in Atlanta.
Spieth began the week with a 200-point lead over Thomas, with world number one Dustin Johnson, Marc Leishman and Jon Rahm in contention.
As the situation fluctuated in the final round, Spieth was projected to win the FedEx Cup after holing his approach to the 10th for an eagle and tapping in for birdie on the 13th.
But a bogey on the 15th effectively ended his chances as Thomas moved into a share of the lead for the tournament with birdies on the 16th and 17th, only for Schauffele to hold his nerve and birdie the last to win.
"As a competitor you are mad that you didn't win the tournament but then you realise what an unbelievable honour this is, the fact that you can win something over the entire course of the season," said Thomas.
Schauffele, who collected more than $3.5m (£2.6m) on Sunday, said: "I'm a little speechless. I thought I'd missed the putt to win the tournament and fortunately it just lipped in. I was very relaxed for most of the day and got really nervous when I saw the leaderboard on 16."