NEW YORK -- Former top-five player James Blake says he will retire from tennis after the U.S. Open.

The 33-year-old Blake announced his decision at a news conference at Flushing Meadows on Monday, the opening day of the year's last Grand Slam tournament.

The American, who attended Harvard before turning pro in 1999, reached a career-high ranking of No. 4 in 2006. He is currently 100th and has a 9-13 record this season heading into his first-round match against Ivo Karlovic in the U.S. Open.

Blake reached three Grand Slam quarterfinals, including two at the U.S. Open, losing at that stage to Andre Agassi in 2005 and to Roger Federer in 2006. Blake's announcement comes a year after his friend and former U.S. Davis Cup teammate, Andy Roddick, retired after the U.S. Open.