Paul Pierce scored 33 points and Kevin Garnett had 22 points, 12 rebounds and six assists to lead the visiting Celtics over the Lakers, 110-91.
Boston took the lead in the first quarter and never relinquished it. Each time the Lakers threatened, the Celtics pulled away again.
Kobe Bryant scored 22 for Los Angeles, going just 6-for-25 from the floor. Lamar Odom had 14 points and 10 rebounds.
The victory in the final of two meetings between the teams this season ran Boston's NBA-best record to 26-3 and extended its winning streak to six straight. It also ended a four-game winning streak by the Lakers, who still have won 10 of their last 13.
The Celtics prevented Lakers coach Phil Jackson from moving ahead of Boston Hall of Fame coach Ray Auerbach on the career wins ladder. Jackson remained tied with Auerbach for seventh on the all-time list with 938 victories.
Ray Allen added 19 points for Boston and Tony Allen, filling in for Rajon Rondo, had 16.
* At Denver, Baron Davis scored 28 points and Stephen Jackson added 23 to help Golden State beat the Nuggets, 105-95, ending a seven-game losing streak in Denver.
Golden State last won in Denver on Feb. 24, 2003.
* At San Antonio, Tony Parker and Tim Duncan each scored 24 points and the Spurs beat Memphis, 111-87. Duncan grabbed 17 rebounds and Parker had nine assists.
* At Sacramento, Amare Stoudemire scored 31 points and grabbed 17 rebounds to lift Phoenix over the Kings, 117-102.
* At New York, Ben Gordon scored 25 points, leading Chicago over the Knicks, 100-83.