Tournament favorites Stan Wawrinka and Juan Martin del Potro were both bounced out Basel on Friday. Del Potro’s run came to an end at the hands of Kei Nishikori 7-5, 6-3.

“I saved a lot of important points with my serve,” said Nishikori. “I played good tactics today.”

Later, qualifier Mischa Zverev stunned Wawrinka 6-2, 5-7, 6-1 to reach his second tour semifinal.

Zverev will next face Marin Cilic who was a winner over Marcel Granollers 6-3, 6-3. Nishikori will meet Gilles Muller who saved a match point over Federico Delbonis.