Grigor Dimitrov came through a tough match against 30th seed Andrey Rublev to progress to the Australian Open fourth round.
The Bulgarian won 6-3 4-6 6-4 6-4 in high temperatures on Rod Laver Arena.
Third seed Dimitrov struggled at times but won a second consecutive match lasting over three hours, following his five-set win over Mackenzie McDonald.
The 2017 semi-finalist will play either Jo-Wilfried Tsonga or Nick Kygrios in the last 16.
“These are most important matches when things are not working and I am able to find a way,” Dimitrov, 26, said.
“Physically I am feeling good and the heat didn’t scare me. That is a good sign.”
Elsewhere, Spanish 10th seed Pablo Carreno Busta progressed with a 7-6 (7-4) 4-6 7-5 7-5 win over Gilles Muller.