Milos Raonic was made to toil in a hard-fought win over Bernard Tomic, but Marin Cilic breezed into the Istanbul Open semi-finals with his 400th career win.
Raonic, playing just his second match back from a hamstring injury that forced him out of the Monte-Carlo Masters, had to battle hard for a 7-6 (7-4) 7-6 (8-6) win against Tomic.
There was nothing to split the two during the opening set, but the Canadian earned a mini-break in the tie-break and that proved enough to win the first set.
Raonic staved off a break point in game nine of the second before holding his serve in a second breaker to deny his opponent the second set, winning the next two points to see him off.
Raonic will face Viktor Troicki in the next round, the Serbian advancing after his compatriot Laslo Djere retired a set down.
While the top seed toiled, Cilic took less than 46 minutes to see of Steve Darcis in an incredibly one-sided quarter-final.
The Croatian fired down seven aces and converted all five break points that came his way to complete a thumping 6-1 6-1 win.
The world number eight will face Diego Schwartzman in the last four after the Argentine overcame Dusan Lajovic 7-5 6-2.