Three-time Australian Open runner-up Andy Murray won five unanswered games to power past fellow seed Grigor Dimitrov 6-4 6-7 (5-7) 6-3 7-5 for a spot in the quarter-finals on Sunday.
Dimitrov was leading 5-2 in the fourth and serving for the set before British world number six Murray - a finalist at the Australian Open in 2010, 2011 and 2013 - blitzed his faltering and inexperienced opponent on Rod Laver Arena.
The 10th seeded Bulgarian simply had no answer as Murray, who dropped a set for the first time at Melbourne Park, set up a showdown with local favourite Nick Kyrgios after three hours and 32 minutes on court.
An upbeat Dimitrov stormed out of the blocks, taking a 3-1 lead after claiming the break in the second game following an unsuccessful Hawk-Eye challenge from Murray.
Murray slowly began to find his rhythm and he broke back in the fifth game as Dimitrov fired a forehand into the net, before the Brit levelled the match at 3-3.
After soaking up significant pressure at the start of the set, a visibly emotional Murray took a 5-4 lead by breaking serve with a powerful forehand winner down the line.
And Murray successfully served out the set with an ace – his fifth of the opener.
Murray and Dimitrov continued to go head-to-head in the second set, with a break apiece and the score level at 4-4.
Dimitrov managed to fend off two break points, holding serve after a 12-point game.
He was unable to dig himself out of a 15-40 hole in the 10th game, though, sending a drop volley wide as Murray broke.
However, Dimitrov broke back immediately, regaining the break and forcing a tie-break after Murray failed to serve out the set.
Dimitrov served up plenty of entertainment en route to taking the tie-break, particularly on the sixth point as he found the line with a stunning backhand following an unsuccessful overhead smash from Murray.
The third set followed a similar script, with neither player able to pull clear. But Murray – after three break points – eventually grabbed a 5-3 advantage before serving out the set with a 94 per cent success rate on his first serve.
Two-sets-to-love down, Dimitrov raced out of the blocks in the fourth by winning the first three games. He consolidated the break until he served for the set in the ninth game.
The young Bulgarian imploded, though, dropping his serve to hand Murray an avenue back. And Murray grabbed the opportunity with both hands, winning the final five games to seal his spot in the last eight at the Australian Open and improve his head-to-head record against Dimitrov to 5-2.