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 [ Images ] 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 [ Images ] 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 [ Images ] from the top spot next week, will next face either former world number one Amelie Mauresmo [ Images ] or Flavia Pennetta [ Images ]