Melbourne - David Goffin wore down Dominic Thiem in intense heat to become the first Belgian man to reach the quarter-finals of the Australian Open on Monday.
The 11th-seeded Goffin equalled his best Grand Slam showing in reaching the last eight with a 5-7, 7-6 (7/4), 6-2, 6-2 win over the eighth-seeded Austrian in two hours 44 minutes.
Goffin's win in the second-set tiebreaker proved crucial as he powered on to victory on Rod Laver Arena, where ambient temperatures were above 35 Celsius.
"I kept fighting, that was definitely key winning the second-set tiebreaker where I made some good returns," Goffin said.
"I continued to push on in the rallies and I'm really happy to win. Mentally, I'm tired."
Goffin knocked Thiem out in the third round of last year's Australian Open, before losing to the Austrian in the quarters at the French Open.
Goffin won on his second match point when Thiem netted a service return. It was the Belgian's first victory over a top 10 player at a major.
The Belgian, who reached the last eight at Roland Garros last year, will next face either Bulgarian 15th seed Grigor Dimitrov or Uzbek wildcard Denis Istomin in the quarters.
"Grigor is playing so well since the beginning of the season, winning in Brisbane, and is playing so well in the tournament, while Istomin is on fire," Goffin said.
Results from the Australian Open on Monday (x denotes seeding):
David Goffin (BEL x11) bt Dominic Thiem (AUT x8) 5-7, 7-6 (7/4), 6-2, 6-2
Johanna Konta (GBR x9) bt Ekaterina Makarova (RUS x30) 6-1, 6-4
Serena Williams (USA x2) bt Barbora Strycova (CZE x16) 7-5, 6-4
Mirjana Lucic-Baroni (CRO) bt Jennifer Brady (USA) 6-4, 6-2