Victor Hanescu of Romania saved two match points before beating top-seeded Gael Monfils 2-6, 7-6 (7), 6-4 in the first round of the Mercedes Cup on Wednesday.
The match was suspended because of rain on Tuesday with Monfils leading 4-2 in the first set. After clinching the set when the match resumed on Wednesday, the Frenchman had two match points in the second-set tiebreaker, but Hanescu saved them and went on to complete his first win over a top-10 player after 11 losses.
Monfils reached the final of the tournament last year, only to be forced to drop out of the match against Albert Montanes of Spain because of injury.
Montanes also lost on Wednesday, going down 2-6, 6-4, 6-3 to fellow Spaniard Pablo Andujar.
Marcel Granollers of Spain defeated seventh-seeded Andreas Seppi of Italy 6-3, 3-6, 6-1.
Six of the eight seeded players have lost in the first round.