BOSTON(AP) Dirk Nowitzki had 37 points, scoring nine in a row during a third-quarter run that gave the Mavericks the lead for good, and Dallas beat the Boston Celtics 99-90 on Monday night. Jason Kidd scored 13 points and added 17 assists for the Mavericks, who had lost three of their previous four games, including a 22-point loss at Toronto on Sunday. Paul Pierce scored 24 points, Ray Allen scored 21, Kendrick Perkins had 14 points and 12 rebounds and Rajon Rondo had 12 assists for Boston, which has lost three straight at home. The Celtics have lost four of their last six overall, and they are 4-7 since beating the defending Eastern Conference champion Magic in Orlando on Christmas Day. The Celtics led by 11 in the first half and had a 65-60 lead with 4:48 left in the third. But Erick Dampier drove for a basket and Nowitzki hit a jumper from the left side to give the Mavs a 69-68 lead and then a jumper from the top of the key for his ninth consecutive point. Shawn Marion scored on back-to-back fast breaks to complete the 15-3 run and make it 75-68 at the end of three; the Mavericks shot 80 percent from the floor in the third quarter. It was 79-75 when the Mavs scored 14 straight points, including back-to-back 3-pointers from Kidd and Jason Terry. The Celtics cut it to 13 points, 93-80, before Eddie House missed a 3-pointer and, after Boston got the offensive rebound, missed another. The Celtics were again without Kevin Garnett, who has missed the past nine games with a hyperextended right knee. But they got Rasheed Wallace back after he missed three games with a sore left foot. Pierce, who banged knees with Shelden Williams in practice, started and played 35 minutes. NOTES: During halftime, Boston coach Doc Rivers and Mavericks coach Rick Carlisle, a former Celtic, presented former Celtics coach Tommy Heinsohn with the first Chuck Daly Achievement Award for contributions to coaching. ... Dallas is 12-2 after a loss. ... Perkins came out for the second half with a bandage under his eye. ... Pierce, Rondo, Williams and J.R. Giddens wore gray shoes as a tribute to Martin Luther King Jr.