(Updates with Federer's match)

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Switzerland's Roger Federer defeated Czech Jan Hajek 6-4, 6-3 Thursday to advance to the quarterfinals of the German Open in Hamburg, keeping alive his bid for a fifth title.

The top-seeded Swiss, who won this title in 2002, 2004, 2005 and 2007, scored his second straight victory since switching to a new, larger racquet, dominating his service games throughout the one hour, 12-minute match en route to the easy victory.

Federer only connected on 51 percent of his first serves for the contest but was only broken once thanks to a 71 percent winning percentage on his second-serve points.

The Swiss world No. 5 also put constant pressure on Hajek's service games, earning 13 break points and converting three of those chances.

The 31-year-old Federer, who made the racquet change after a shocking second-round defeat at Wimbledon that dropped him to his lowest ranking in a decade, will take on Germany's Florian Mayer - a 7-6 (7-1), 6-2 winner over Spain's Feliciano Lopez - in Friday's quarterfinals.

In other action Thursday, second-seeded Tommy Haas scored a 6-2, 6-4 victory over Argentina's Carlos Berlocq, who was fresh off winning his first career ATP singles title at last week's Swedish Open. The 11th-ranked Haas, who is enjoying a late-career renaissance at age 35, will square off against Italy's Fabio Fognini in the quarterfinals.

Argentines Juan Monaco and Federico Delbonis also won their round of 16 matches Thursday against France's Benoit Paire and Russia's Dmitry Tursunov, respectively, while third-seeded Spaniard Nicolas Almagro routed countryman Guillermo Garcia-Lopez 6-2, 6-3.

Almagro will next take on Monaco, the defending champion, for a spot in the semifinals of the German Open, which used to be a major tune-up for the French Open but has been a lesser-tier event since 2009.

Delbonis will square off against Spain's Fernando Verdasco, who advanced to the quarterfinals when his opponent, 2013 Wimbledon semifinalist Jerzy Janowicz of Poland, retired while trailing 7-5, 4-0. EFE