BOSTON — Al Horford turned back the clock in his return from a two-game absence with a concussion. The former Gator scored 21 on 8-of-9 shooting to help the Celtics hang on to beat the Raptors 95-94 on Sunday for their 12th straight victory. "He's playing young again," teammate Terry Rozier said. Horford, in his 11th season, had 15 points, 10 rebounds and nine assists against his former team in Atlanta on Monday, the day an elbow to the head from Kent Bazemore sent him into the NBA's concussion protocol. Boston was playing without Kyrie Irving after he took an inadvertent elbow to the face from teammate Aron Baynes on Friday night against the Hornets. Irving has a minor facial fracture but has not been diagnosed with a concussion as initially feared. Jaylen Brown added 18 points, and Rozier had 16 off the bench. DeMar DeRozan scored 24, and Kyle Lowry had 19 and seven rebounds for Toronto. "They are the best team in the NBA right now, 12 in a row," Lowry said. "They're playing unbelievable, everyone is picking up slack." DeRozan missed a potential go-ahead stepback jumper with 19 seconds left. Boston rookie Jayson Tatum got the rebound but elbowed Fred VanVleet in the face for a foul. DeRozan had another look but missed a turnaround jumper with two seconds left. Serge Ibaka scooped up the rebound but lost the ball as time expired. "He shook him, he was wide open, vaulted up, and I'll take that shot 999 times out of 1,000," Raptors coach Dwane Casey said about DeRozan's effort. Game Highlights: James Harden had 26 points and 15 assists to lead the visiting Rockets past the Pacers 118-95. … Paul George scored 37, Russell Westbrook added 27 and the host Thunder defeated the Mavericks 112-99. … Tobias Harris scored 25 as the host Pistons beat the Heat 112-103.Around the League: Jazz center Rudy Gobert will be out for the next month after an MRI exam revealed a bruised lower leg.