Novak Djokovic fought back to dispatch Marcos Baghdatis 2-6, 6-2, 6-3 on Friday, sending him into the ATP Swiss Indoors semifinals and confirming his return to form.
The Serbian top seed set up a clash with rising Japanese star Kei Nishikori, a 6-4, 5-7, 6-4 winner in nearly three hours over Kazak Mikhail Kukushkin.
Djokovic, competing for the first time in six week after back trouble, fought off a dozen aces from Baghdatis to move into the last four at the event he won in 2009 against Roger Federer.
He dropped serve twice in the opening set but quickly put his game right to steam through in just over 90 minutes.
Djokovic improved to 6-0 over Baghdatis, a player against whom he has struggled, with the Cypriot winning sets in their last four meetings.
Djokovic's win was his 67th of a sensational season against just three losses.
The 32nd-ranked Nishikori will be competing in his third semi-final in six weeks after making it to the final four last month in Kuala Lumpur and at the Shanghai Masters, which was the best showing of his career.
"It's a great feeling," he said after the victory. "I knew this would be tough, but another semi-final is a great result for me.
"I was up a break in the second set and didn't really think I'd be playing a third but I struggled a bit. I played the last three games of the match very strong."
The 21-year-old began his week in Basel with his second career top 10 win, putting out year-end final contender and fourth seed Tomas Berdych, having previously upset Jo-Wilfried Tsonga in the Shanghai second round.
The Florida-based Nishikori took 20 minutes short of three hours to win his sixth quarter-final from seven played this season.
The match with Kazak Kukushkin was break-filled, with Nishikori converting seven of 16, while losing his own serve six times.