Roger Federer struggled in his first match since his Wimbledon humiliation when he had to come back from a set down to defeat Germany`s Daniel Brands in his Hamburg opener on Wednesday.
The 31-year-old, top-seeded Federer won 3-6, 6-3, 6-2 against the world number 58, who was celebrating his 26th birthday, to reach the third round of a tournament he last played in 2008.
It was his 30th career win at the tournament.
Federer, now ranked five in the world, his lowest point for a decade, goes on to face Jan Hajek of the Czech Republic for a quarter-final spot.
The Swiss great is using this event and the Gstaad tournament, which starts on July 22, to bounce back from his shock Wimbledon exit ahead of next month`s US Open.
Federer crashed out of Wimbledon, where he was the seven-time champion, at the hands of Ukraine`s 116-ranked Sergiy Stakhovsky in his worst Grand Slam defeat for a decade.
The second round loss ended his run of 36 consecutive Grand Slam quarter-final appearances, having not gone out of a major before the last eight since the 2004 French Open.
Hajek reached the third round with a 6-4, 2-6, 6-4 win over Latvian 15th seed, Ernests Gulbis.
Tommy Haas, who first competed at Hamburg in 1997, will play in-form Carlos Berlocq in the third round.
Second seed Haas was made to work hard for a 6-1, 4-6, 6-4 victory over qualifier Blaz Kavcic of Slovenia.
Last week`s Swedish Open champion, Berlocq, continued his run of form by beating Slovak 16th seed Martin Klizan 4-6, 6-1, 7-6 (7/5).
Argentine fifth seed Juan Monaco got his title defence off to a winning start when he beat Gael Monfils 6-4, 6-4 in 73 minutes for a place in the third round.
Qualifier and world number 114 Federico Delbonis held his nerve to knock out 2006 champion Tommy Robredo, the 10th seed, 6-1, 4-6, 6-4.
Guillermo Garcia-Lopez improved to 5-1 in his head-to-head record against 13th seed Mikhail Youzhny in a 6-3, 6-7 (3/7), 6-2 win.
Youzhny saved six match points in the second set.