SAN ANTONIO — Tim Duncan is undergoing a renaissance after signing a three-year extension with the Spurs in the offseason. Duncan, who briefly contemplated retirement, entered Saturday night’s game averaging 17.8 points, 10.2 rebounds, 2.6 blocks, and 2.4 assists in 30 minutes. And though he scored only 5 points (on 2-of-13 shooting) in a 103-88 win over the Celtics, he still pulled down 12 boards and had two blocks.

“He’s competitive,” Celtics coach Doc Rivers said before the game. “I really believe it’s that simple. I really do. Last year in the Oklahoma [Western Conference final] series he struggled with his shot. He struggled with his free throws. I guarantee you this summer, he put the time in the gym and he’s back. It’s amazing.