Daniil Medvedev mounted a stirring comeback to beat Felix Auger-Aliassime in their quarterfinal in Melbourne
Daniil Medvedev saved match point as the Russian star was forced to dig deep before staging a brilliant fightback to beat Canada's Felix Auger-Aliassime and move into the Australian Open semifinals.
An out-of-sorts Medvedev was staring down the barrel of an upset as ninth seed Auger-Aliassime opened up a two-set lead in Melbourne and had match point on the Medvedev serve in set four.
But despite being far from his best in a sluggish performance, the world number two roused from his slumber to break the resolve of his 21-year-old rival and see out the contest 6-7 3-6 7-6 7-5 6-4, in an epic lasting almost five hours on Rod Laver Arena.
Installed as the tournament frontrunner Down Under after the deportation of nine-time champion Novak Djokovic, US Open winner Medvedev is still on course to become the first man to follow up a maiden Grand Slam title with victory at his next appearance at a major.
But those chances hung in the balance on what was a limp night for Medvedev for large periods, before he finally conjured up some form to set up a semifinal with Greek fourth seed Stefanos Tsitsipas, who had been impressive in his straight-sets quarterfinal victory over Jannik Sinner earlier on Wednesday.
Medvedev almost pays price for slow start
In a repeat of last year's US Open semifinal - which Medvedev won in straight sets - this time Auger-Aliassime offered a much tougher obstacle for the big-serving Russian.
A tight opening saw the pair trade breaks of serve late in the first set before Medvedev made two untimely double-faults in the tiebreak, allowing Auger-Aliassime to take the set.
The warning signs were already there for Medvedev, who looked strangely weary in the face of relentless pressure and an all-action display from his Canadian opponent.
A flustered Medvedev continued to flail as Auger-Aliassime broke him at the first attempt in the second set, with the Russian sending an inviting forehand wide of the line - summing up the sloppiness which characterized his night.
The inspired Canadian consolidated with ease to see out the set and leave Medvedev facing a mountain to climb if he wanted to haul himself back into the match.
Auger-Aliassime picked up where he left off in set three as Medvedev - grunting heavily on some of his shots - was forced to stave off break point as early as game three.
The Russian attempted to rouse the crowd after winning a brilliant rally on his serve in game five as the world number two belatedly showed signs of a revival.
But the pressure from Auger-Aliassime did not relent and Medvedev was seen gesturing to his coaching team in desperation as the set remained on serve and went to a second tiebreak of the match.
The rain began to fall on Rod Laver Arena, forcing a delay as the roof was closed, but it didn't halt Medvedev's newfound momentum as suddenly it was Auger-Aliassime who was afflicted with some sloppy shot-making.
Medvedev took the tiebreak 7-2, letting out a roar as he kept his tournament hopes alive.
Big screen bother
Tournament favorite Medvedev was far from playing his best tennis but continued to dig deep, grumbling at one stage to the match umpire about the face of his rival being projected on the big screen as he prepared to return serve - calling it a "stupid" distraction.
Medvedev was unhappy at the big screen in Melbourne. Twitter
Down 4-5 in the set and left serving to stay in the championship, another double-fault from Medvedev brought up match point for Auger-Aliassime - but thankfully for the Russian he saved his skin with a timely ace before leveling up the set at 5-5.
Medvedev released another guttural roar into the Melbourne night and backed it up his defiance by breaking Auger-Aliassime for the first time in the match immediately afterwards.
The Canadian showed his own mettle by saving three set points but the tide had firmly turned in Medvedev's favor as he served out from deuce to level a thrilling match at two sets apiece.
Medvedev staved off three break points on his opening service game in the decider but continued his momentum, breaking Auger-Aliassime in game three to swing the tie further in his favor.
Auger-Aliassime required treatment on his foot but proved he wasn't going down without a fight, earning break point on the Medvedev serve in game eight before the Russian ruthlessly averted the danger.
Medvedev found himself 15-40 down as he attempted to serve out the match - hinting at one final twist - but again bailed himself out to win a titanic tussle and move into the semifinals for the second time in Melbourne in his career, as the 25-year-old aims to go one better than last year when he was beaten in the final by Novak Djokovic.
Daniil Medvedev kept his Australian Open hopes alive. Getty Images
Medvedev will now have to rest and recuperate from his exertions before taking on Greek rival Tsitsipas in Melbourne on Friday.
The other semifinal will be contested on the same day by 20-time Grand Slam champion Rafael Nadal and Italian seventh seed Matteo Berrettini.