Wells opened the scoring with a homer against Mark Buehrle in the second that hit the left field foulscreen, his fifth of the season and second in two days.
After World Peace was called for a foul on an illegal screen, denying Bryant a chance to take the final shot of the half, Bryant and World Peace barked at each other as they made their way up the court.
The Celtics had some momentum midway through the third period, when they went on a 9-2 run, but it was snuffed out by a questionable offensive foul called on Boston's Kevin Garnett, who'd set a hard screen at halfcourt.