Mardy Fish [Images] ruined Gael Monfils's 22nd birthday celebrations by handing the French 32nd seed a 7-5, 6-2, 6-2 drubbing in the fourth round of the US Open [Images] on Monday.

Monfils would have hoped to mark his big day by reaching the quarter-finals at Flushing Meadows for the first time. Instead it was Fish who celebrated a personal landmark.

After trampling seeds Paul-Henri Mathieu and James Blake in the previous two rounds, the 35th-ranked American kept up his run by meting out similar treatment to Monfils.

Monfils took an injury timeout while trailing 3-0 in the second set to get his right leg strapped just under his knee but that failed to change his fortunes and he bowed out by slamming a forehand into the net.

Fish will next face either top seed Rafael Nadal [Images] or fellow-American Sam Querrey.

Meanwhile, Dinara Safina's pursuit of a maiden Grand Slam title gathered momentum when she defeated German qualifier Anna-Lena Groenefeld 7-5, 6-0 to reach the quarter-finals.

The Russian sixth seed has reached six finals in her last seven tournaments.

Groenefeld tried her best to rattle Safina when she stormed back from 4-2 down in the opening set to level at 5-5.

But that ended up being the last game the 141st ranked Groenefeld won as Safina pounded down a string of sizzling groundstrokes to win in 75 minutes.

The Russian, who is one of four players who could topple Ana Ivanovic from the top spot next week, will next face either former world number one Amelie Mauresmo or Flavia Pennetta

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