Basel - Juan Martin del Potro overcame a nose bleed and a stubborn underdog opponent to reach his second straight final at the Swiss Indoors on Saturday as he defeated Edouard Roger-Vasselin 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.
Instead of serving into a 5-3 lead, Del Potro instead double-faulted for break points and lost serve as he let Roger-Vasselin back into it.
The 65th-ranked Frenchman, playing only his second semi-final of the season, took advantage, holding for a 5-4 lead and breaking the Argentine again to take the set after Del Potro saved a first set point with his fifth ace but hit out on a second.
The seed steadied in the final set, taking a 4-0 advantage and eventually finding a match point with a forehand down the line. A backhand to the net from his opponent ended the drama after just over two hours.
"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 a another final here."
Del Potro will next play either five-time champion Roger Federer, who faces 40th-ranked Canadian outsider Vasek Pospisil, in the other semi-final.
Federer can clinch a place in London by winning a sixth title here on Sunday and qualifying into the year-end field for the 12th consecutive year, according to ATP calculations.
Del Potro will be playing in his sixth final of the year and 24th overall. He improved to 47-13 on the season as he bids for a fourth title in 2013.