Kei Nishikori saved a match point with a perfect top-spin lob and fought back to beat Gilles Muller 4-6, 7-6 (3), 6-3 in the Swiss Indoors semifinals on Saturday.
The No. 5-ranked Japanese faced an upset loss to the 37th-ranked left-hander from Luxembourg when trailing 4-5, 30-40 in the second set.
Nishikori went behind the baseline to retrieve Muller's backhand volley approach shot and lifted a forehand lob.
"My arm was shaking, it was match point for him," said Nishikori, who saved a second match point soon after.
The third-seeded Nishikori dominated the second-set tiebreaker and completed the win in 2 hours, 15 minutes.
Nishikori, who lost the 2011 Basel title match to Roger Federer, will play fourth-seeded Marin Cilic of Croatia or unseeded Mischa Zverev of Germany on Sunday.