- Murray wins last five games to progress
- Dimitrov defeated after 3 hours and 32 minutes
- The Briton faces Australia's Kyrgios in last eight
- Murray reaches his 16th straight Slam quarter-final
Andy Murray won a gruelling late-night contest with Grigor Dimitrov to reach his sixth consecutive Australian Open quarter-final.
The British number one came through 6-4 6-7 (5-7) 6-3 7-5 in three hours and 32 minutes.
A fifth set had looked likely but Murray won the last five games in row, sealing victory with a forehand that clipped the net and dropped over.
He goes through to face Australia's Nick Kyrgios in the last eight.
Murray will be playing in his 16th consecutive Grand Slam quarter-final, having lost to Dimitrov at the same stage at Wimbledon last year.
Kyrgios made his first and only major quarter-final to date at the same tournament after a stunning win over Rafael Nadal.
The 19-year-old won a five-set thriller against Andreas Seppi on Sunday that dominated Melbourne Park to such an extent that the cheering from Hisense Arena could be heard on Rod Laver Arena.
|BBC Sport tennis correspondent Russell Fuller|
|"The nine games out of 11 Murray won in response to Dimitrov's barnstorming start was almost as good as it gets, and even though the match should not have spilled over into Australia Day, Murray has now convinced judges like Goran Ivanisevic that he can reach at least the final.|
|"Dimitrov played very well until collapsing under some late fourth set pressure, but Murray was able to carve out break points almost at will throughout the match.|
|"He will need to take more of those opportunities in the days to come, but he does now look like a genuine Grand Slam contender once again."|
When the result was clear and the home favourite had won, Murray and Dimitrov were forced to wait until the excitement subsided.
By that point Murray had already taken the first set from 3-0 down, seizing control after a blistering opening from the Bulgarian 10th seed.
The Scot, 27, was returning superbly and creating chance after chance on the Dimitrov serve, twice going a break clear in the second set only to hand the advantage back.
An increasingly tentative Murray failed to serve out the set at 6-5, double-faulting on break point, and was on the back foot in the ensuing tie-break.
Dimitrov, 23, surged forward, moving 4-2 in front with a stunning backhand pass that had the crowd on their feet, and converting his third set point.
With the match back in the balance, it was Murray who took control in the third only for his frustration to grow as break points passed him by.
Umpire Jake Garner felt the full force of Murray's temper when the official failed to spot what appeared to be a double bounce, but Murray regained his composure to break for a 5-3 lead.
|67||1st serve %||69|
|77||1st serve win %||67|
|40||2nd serve win %||34|
|Match time: 3hr 32mins|
The set soon followed only for Dimitrov to respond once again, breaking early in the fourth with a fizzing backhand pass that crumpled Murray's attempt at a volley.
At 5-2 down, even Murray must have been thinking about a decider, but he saved a set point with a heavy forehand and watched as Dimitrov handed over his advantage.
Three forehand errors gave up the break at 5-3, and a disastrous 11th game saw the Bulgarian drop serve to love before violently breaking his racquet in two after Murray swatted away a return winner.
A match of such fluctuating fortunes hinted at another swing when Murray was pegged back to 30-30 while serving for the match, but the sixth seed saw out the next two points to keep his title hopes on track.
"I thought I played well," said Murray. "I thought Grigor started the match extremely well. He came out very aggressive, very explosive.
"But it's tough to keep that sort of level of intensity up. And then once I got myself into the match, I felt like I was able to dictate a lot of the points. I thought tactically I played a good match."
Dimitrov said: "If you lose, you obviously haven't done some things right. I'm happy that I competed at a good level and it takes a player like Andy to beat me like that.
"I'm just disappointed because it's not the result that I wanted. For sure I could have done some things better."