Andy Murray has hailed Kyle Edmund's courage after Britain's last Australian Open hope conjured the finest win of his career to surge into the last 16 at Melbourne Park.
While world No.1 Rafael Nadal cruised and third seed Grigor Dimitrov advanced with a comfortable four-set win in the "cooler" afternoon conditions, Edmund fought back from two sets to one down in a 40-degree furnace to keep the Union Jack flying.
Edmund appeared ready to fold on shadeless show court 2 before battling back for a 7-6 (7-0) 3-6 4-6 6-0 7-5 victory over Nikoloz Basilashvili.
Otherwise keeping long rallies to a minimum, Edmund won an extraordinary 20-minute, 36-point game early in the fourth set that seemed likely to break the Georgian's spirit.
Basilashvili lost the next four games in quick fashion to allow Edmund to tie up the match at two sets apiece.
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But Basilashvili came back to life in a tight decider as both combatants cooled themselves with ice towels at every changeover before finally submitting after three hours and 34 minutes of desperate toil.
With Murray absent as he recovers from hip surgery and women's No.9 seed Johanna Konta eliminated in the second round, Edmund is the last remaining British interest in the singles at Melbourne Park.
"Physical test passed. Mental strength passed. I reckon that's biggest win of @kyle8edmund career! Well done kedders," five-time finalist Murray tweeted with double applause emojis.
Edmund's reward is a fourth-round clash on Sunday with Italian Andreas Seppi, who came through a searching five-set win of his own, conquering big-serving Ivo Karlovic after three hours and 51 minutes.
Seppi overcame 52 aces from 38-yera-old Karlovic to emerge a 6-4 7-6 (7-4) 6-7 (3-7) 6-7 (5-7) 9-7 winner on Hisense Arena, the same venue where he knocked out Nick Kyrgios last year.
Should he beat Edmund, he would reach the quarter-finals of a grand slam for the first time in 52 attempts.
Spanish 10th seed Pablo Carreno Busta outlasted veteran Gilles Muller from Luxembourg 7-6 (7-4) 4-6 7-5 7-5 in another gruelling encounter lasting three hours and 18 minutes.
Having not progressed beyond the third round in any of his first 14 major campaigns, Carreno Busta has reached the quarter-finals at last year's French Open, the semis at the US Open and the last 16 at Melbourne Park in his past three slams.
His next opponent will be 2017 Wimbledon runner-up and former US Open champion Marin Cilic after the Croat took out American Ryan Harrison 7-6 (7-4) 6-3 7-6 (7-4).
Dimitrov prevailed 6-3 4-6 6-4 6-4 against Russian young gun Andrey Rublev.
The Bulgarian will meet Nick Kyrgios after Australia's last man standing held his nerve for a tense 7-6 (7-5) 4-6 7-6 (8-6) 7-6 (7-5) victory over France's former finalist Jo-Wilfried Tsonga in the feature night match.
Nadal demolished Bosnian Damir Dzumhur 6-1 6-3 6-1 and next plays Argentine Diego Schwartzman, a 6-7 (1-7) 6-2 6-3 6-3 winner over Alexandr Dolgopolov.
