The fifth-seeded Richard Gasquet and sixth-seeded Mikhail Youzhny crashed out in the first round of the Gerry Weber Open on Tuesday.
Robin Haase of the Netherlands defeated Gasquet 6-4, 6-4, and Ivo Karlovic of Croatia hit 22 aces on his way to a 6-3, 6-4 win over Youzhny.
Haase next faces Colombia's Alejandro Falla, who defeated Poland's Lukasz Kubot 6-2, 3-6, 6-3, and Karlovic meets Lu Yen-hsun, who prevailed 7-6 (2), 6-7 (11), 7-6 (5) over Croatian qualifier Mate Pavic.
Also, Steve Johnson beat French lucky loser Albano Olivetti 6-4, 6-2.
Tommy Haas was due to play the American but withdrew on Monday with a right shoulder injury.
Russia's Teymuraz Gabashvili defeated Ukrainian Illya Marchenko 6-7 (9), 6-4, 7-6 (4) and Frenchman Gael Monfils beat Germany's Benjamin Becker 6-1, 7-5.