I don't think any one player won this game although it can be said that Pierce might have been most instrumental in the victory. Without the defense that Eddie House, Tony Allen(which I was glad to see he was doing even when his layups and shots weren't falling and he was charging towards the basket with his head down without abandon), Big Baby, Rondo, Perk and Powe.
The Raptors scored 9 points in 3 minutes and 46 seconds to start the second half and the score was 57-42. The Celtics outscored the Raptors 52-30 form that point on and every single layer that hit the court was responsible because the most stifling defense played this season was displayed for the last 20:14 of that game. It was a defensive coaches wet dream.
Simply a thing of beauty and as much as Pierce and Ray and KG led the scoring and were all clutch from that point forward, this game is lost if not for the total team defense that exhibited by every player that hit the floor.