Bernard Tomic of Australia was the first seeded player to be eliminated at the Swiss Open on Monday, losing 6-0, 6-4 to Benoit Paire of France in the first round.
The 47th-ranked Paire swept the first set despite landing only three first serves against the 45th-ranked Tomic, who was seeded eighth after getting a wild-card entry to the clay-court tournament.
Paul-Henri Mathieu was another Frenchman who had to overcome serving problems to win 6-3, 7-6 (4) against Igor Andreev of Russia. Mathieu, a former top-20 player, double-faulted 10 times but saved all seven break points he faced.
The 30-year-old Mathieu fell to 733 in the rankings after a left knee injury sidelined him last season.
Jan Hernych of the Czech Republic beat Matteo Viola of Italy 6-3, 2-6, 6-3, while Martin Fischer of Austria ousted Sandro Ehrat of Switzerland 6-2, 6-4.