Defending champion Andy Roddick [Images] battled through to the quarterfinals of the Stella Artois Championships on Thursday with a testing 6-2, 3-6, 6-4 victory over Slovakian Karol Beck.

Croatian fifth seed Mario Ancic, however, was eliminated when he lost 7-5, 1-6, 6-3 in the third round to gifted French teenager Richard Gasquet in the pre-Wimbledon grasscourt event.

Second seed Roddick, winner at Queen's in 2003 and 2004, was second best for much of his match against Beck but the world number 44 cracked when serving at 4-5 in the third set.

Beck doubled-faulted twice in succession to hand the American an unexpected match point and blazed a backhand out to lose his serve and with it a match in which his drop shots and variation caused Roddick all sorts of problems.

"He played well, very smart and very crafty," said Roddick, the runner-up at Wimbledon [Images] last year. "I'm just happy to get through."

The world number four will play either French seventh seed Sebastien Grosjean, whom he beat in each of the last two Queen's finals, or American James Blake in the last eight.

Tenth seed Gasquet, who has never progressed beyond the first round at Queen's before, took a significant pre-Wimbledon scalp to show he can translate his impressive claycourt form on to the slicker surface.

The 18-year-old, who reached the Hamburg Masters final last month, edged the first set against 2004 Wimbledon semi-finalist Ancic.

After a second set lapse Gasquet dominated the decider to set up a quarter-final against either Briton Greg Rusedski [Images] or Czech Radek Stepanek.

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