Arron Afflalo is usually content to be the quiet sidekick, the team’s No. 2 scorer who is willing to pick up what he can while the offense runs through Carmelo Anthony.

On Tuesday night, however, Afflalo showed he can be much more than a supporting actor when the team needs him to be. With Anthony out with a sprained ankle and Kristaps Porzingis in foul trouble, Afflalo stepped up to score 20 second-half points and vocally pushed his teammates to step it up down the stretch as the Knicks defeated the Boston Celtics, 120-114.

“He led us, for sure,” said Jerian Grant, who scored a career-high 16 points. “I haven’t seen him like that throughout the season. He was talking. He was telling us. He was giving everybody on the floor confidence down the stretch.”

StoryKnicks lose Melo, Porzingis, but beat Celtics

That’s because Afflalo, a nine-year veteran, has the confidence to know that just because he has played one role on a team doesn’t mean he can’t play another if he has to.

“’I’ve been a scorer. I’ve been the number one option, the number two option,” Afflalo said. “I know how to get the job done. My job is not to compete with Melo every day. When he goes down, it’s no problem for me to step into that lane.”

Afflalo finished the game with 24 points, but most telling was the fact that he opened the game 2-for-9, but then went 7-for-9.

advertisement | advertise on newsday

A good friend of Anthony’s, Afflalo had a sick feeling after seeing him fall to the floor after stepping on referee Steve Anderson’s foot late in the second quarter. Carmelo went to the locker room, got retaped and started the second half, though he lasted only 19 seconds.

“I was very concerned,” Afflalo said. “He’s a big part of what we do. We depend on his production. A lot of offensive flow is centered around him. Obviously, I’m capable of picking up slack when he goes down in the immediate sense but we want our team to be completely healthy so we can be the best we can be.

“I told my teammates I’ve accepted the role of being a utility guy. I think for the betterment of my team that it’s best we allow players to do what they do best. Melo’s a great scorer, but I feel I can be a secondary scorer to him, as well as when KP’s not going. For the time that any of those guys aren’t going or are out from injury, I’m available to pick up slack.”