BASEL - Roger Federer earned a rematch with Juan Martin del Potro for his hometown Swiss Indoors title by beating Vasek Pospisil in a tight semifinal on Saturday. Federer advanced to his eighth straight Basel final with a 6-3, 6-7 (3), 7-5 win against the 40th-ranked Canadian. The sixth-ranked Federer faltered when serving for the match at 5-3 in the second set, and fell 3-1 behind in the third before rallying. Earlier, defending champion del Potro also let the second set slip away against an unseeded opponent before beating Edouard Roger-Vasselin of France 6-4, 4-6, 6-2. The Argentine holder was twice seen by the trainer in the second set to deal with one of his not-uncommon nosebleeds. Del Potro was cruising to an apparent easy win with a lead of a set and 4-3 when the wheels briefly came off his game. "I made a lot of mistakes at the end of the second set," said Del Potro, qualified into the year-end World Tour Finals in London starting a week from Monday. "He was right there and took his opportunities. He had nothing to lose and it was a tough match for me. I had all the pressure on me as I was the favourite. But at the end I managed to find my game again and played well. I'm just glad to be into another final here." If Federer wins Sunday, he'll secure his place at the ATP Finals in London. –Agencies