Boston played 53 minutes of basketball against without Paul Pierce, Kevin Garnett, Ray Allen and Rajon Rondo, and yet the Celtics found themselves within one point of the Washington Wizards with five seconds left in overtime.
Yet Carlos Arroyo missed the potential game-winner with two seconds remaining, giving the Wizards a 95-94 overtime victory on Monday night at the Verizon Center.
John Wall paced the Wizards' attack, scoring 24 points and grabbing nine rebounds. Jordan Crawford scored 17, Andray Blatche finished with 16 points and JaVale McGee totaled 13 points and nine rebounds for Washington.
The loss for the Celtics (55-26) locked them into the third spot in the Eastern Conference, meaning that Boston will face the sixth-seeded New York Knicks in the first round of the playoffs while the second-seeded Miami Heat will the face the seventh-seeded Philadelphia 76ers.
Washington (23-58) was held to 40 percent shooting from the field and three-point range while making 25-of-32 free throws in the victory.
Jeff Green, who started alongside Glen Davis, Jermaine O'Neal, Von Wafer and Delonte West, had a stellar performance for Boston, amassing 20 points and 15 rebounds (11 defensive rebounds) for Boston.
Davis also scored 20 points and had four assists and three rebounds for the Celtics, who shot 38.1 percent from the field. Jermaine O'Neal had one of his best games as a Celtic, finishing with 15 points, 13 rebounds and five blocks. West and Wafer both had 11 points and Arroyo finished with seven points to lead the bench scoring for Boston.
West was forced to leave the game with a sprained ankle early in the second quarter after playing just 23 minutes.
Boston will host the New York Knicks in its regular season finale on Wednesday night.