I'd submit Ray's Game 6 performance against the Bulls in 2009. Maybe it's disqualified because we lost the game, but his line was 51 points, 5 rebounds, 3 assists, and three steals and multiple clutch shots. He tied an NBA record with 9 three pointers, and became the first Celtic since John Havlicek to score 50+ in a playoff game.
This is the only other one I could think of, still can't believe we lost that game but I think it was 2OT?
I would also go with any Celtic, particularly KG or Ray Ray, in the Game 6 finals win.
Ray Allen: 26 on 8/12. 7/9 3PM-A, 3 steals, 1 TO
KG: 26 pts on 10/18, 14 rbds, 3 steals, 1 block
Rondo had 21 and 8
Pierce had 10 assists
We utterly humiliated the Lakers. Man that was great.