Gael Monfils, one of a trio of winning French players, returned to wrap up some unfinished business on a wet Wednesday to leave top seed Nikolay Davydenko winless at the Swiss Open.
Davydenko, fifth in the world, has been beaten three times in the first round here.
For a third straight day, unseasonably cold alpine weather failed to cooperate, forcing start-stop play on the clay courts.
Monfils held his nerve from Tuesday evening after failing to serve out the victory in rain, near-freezing temperatures and fading light.
When the pair returned, the number 57 broke Davydenko, then concluded the two-day struggle with a pair of aces, 3-6, 6-4, 7-5.
"It was about the coldest that I've played in. I was very sad not to have finished," said Monfils. "I was only four points away. But I was nervous. I talked to my coach afterwards and saw my errors. I tried to work on that today. I practised serves this morning and did sprints, I knew our match would go quickly, but I was prepared to play a tiebreaker."
Wimbledon semi-finalist Richard Gasquet began his title defense, winning a first-round match over Spain's Rueben Ramirez Hidalgo 6-3, 6-4.
The pair actually played for one hour, 17 minutes, with a rain interruption in the seventh game of the second set lasting nearly an hour-and-a-half.
Gasquet won Gstaad a year ago over Feliciano Lopez.
The third seed, who struck nine aces, saved seven of 10 break points he faced on the high-altitude clay.
"The rain and the altitude made it tough to change," Gasquet said. "Plus, I was really tired from Wimbledon. I beat Roddick at 8pm on Friday and had to come back out on Saturday at noon to face Roger [Federer]."
"The conditions here are a huge change from the grass. It's not easy to switch over just like that. I rested on Monday and got some extra time when our match was postponed on Tuesday. I'm keen to do well here and try to retain my title," said the Neuchatel-based youngster.
Sixth-seeded Frenchman Marc Gicquel booked the first of the quarter-final spots as he put out fellow over-30 Werner Eschauer 6-2, 7-6 (7/4).
The defeat was a rare one for the 33-year-old in Switzerland, who owns four Challenger titles in the country.
Disaster struck the top two seeds, with both Davydenko and Mikhail Youzhny making exits.
Stefan Koubek stunned Youzhny 6-4, 6-3 with the Austrian reversing his luck after winning just three matches in his last ten events.
Former finalist Igor Andreev saved some Russian pride as he beat Spain's Albert Montanes 3-6, 6-3, 6-4 in another match halted the day before in the final set.
Monfils said he was nervous when he tried to close it out against Davydenko on Tuesday.
In other first-round results, Argentine Marcelo Vassallo Arguello ended home participation early, upsetting seventh seed Stanislas Wawrinka 7-5, 1-6, 6-4.
Florent Serra was the lone French loser, falling to Czech Jiri Vanek 6-4, 6-1.
Spadea reaches quarter-finals
Former finalist Vince Spadea reached the quarter-finals at the Hall of Fame Championships when he accounted for Paul Capdeville of Chile 6-3, 7-5 on Wednesday.
Spadea had his serve broken in the first game, but broke back twice to take control of the first set.
"In grass court tennis, anytime you lose serve the first time it's not a good sign," he said. "But I'm ranked higher and have more experience."