BOSTON (AP) - The Gatorade-stained shirt worn by Boston Celtics coach Doc Rivers as the team won its first NBA championship in 22 years has been auctioned for $55,000.

An anonymous bidder bought the shirt, autographed by Rivers and Celtics star Paul Pierce, and the accompanying Gatorade bucket at a charity auction on sports radio WEEI-AM's Web site. The proceeds will benefit the Boston Celtics Shamrock Foundation.

The foundation said Tuesday the high bid of $35,000 came from an anonymous bidder. Gatorade and a second anonymous donor each pledged $10,000 to bring the total to $55,000.

Celtics managing partner and foundation president Steve Pagliuca offered a personal donation of $35,000 to the charity if the winning bidder would share the shirt at certain times for display. No word yet on whether the bidder will accept the offer.