WALTHAM, Mass. -- Boston guard Sam Cassell sparked the Celtics offense in the fourth quarter in Game One, scoring 10 of his 13 points in the fourth quarter.

“All I did was make some shots, something I’m accustomed to doing,” Cassell said. “Once you get the rhythm, it’s cool. This is my first time in a long, long time being the backup, so it’s difficult, but I’m understanding it more and more. I haven’t had this role in 12 years, so now I got it down so I’m enjoying [it], but if you are sitting on the bench and you don’t want to play more, there’s something wrong with you.”

Cassell’s goal is to make the most of every minute he is on the floor. The 38-year-old, 14-year NBA veteran is averaging 6.8 points per game in the playoffs in only 13.9 minutes.

Although Cassell would like to play more, he said yesterday at practice that he was starting point guard Rajon Rondo’s biggest fan.

“I’m his biggest cheerleader, and he’s my biggest cheerleader,” Cassell said.

-ROBERT LEE