Jermaine O'Neal #7 of the Boston Celtics tries to block...

Jermaine O'Neal #7 of the Boston Celtics tries to block a shot by Carmelo Anthony #7 of the New York Knicks in Game One of the Eastern Conference Quarterfinals. (April 17, 2011) Credit: Getty Images

BOSTON -- Jermaine O'Neal trudged toward the bench, headed for a much-needed blow.

There still was 4:42 to play in the third quarter, but the crowd at TD Garden Sunday night felt the need to give him a thunderous ovation because the oft-injured center gave the Celtics a spark after their lethargic first half.

O'Neal made two shots, grabbed two big offensive rebounds, swatted Carmelo Anthony's attempt and drew a charge on Bill Walker. He had asserted himself inside, helping turn the tide in the home team's favor.

The 6-11, 255-pounder nailed a big putback jumper with 1:13 left to square it at 82 -- just one of many big plays he made in the Celtics' 87-85 win in Game 1 of their Eastern Conference first-round series against the Knicks.

"We won the game because of Jermaine O'Neal. That's it," coach Doc Rivers said. "Forget his offense. His defense, his presence, his shot-blocking, his rebounding, his toughness -- and he did it in both halves. He was absolutely wonderful."

So wonderful that Rivers eschewed his usual plan of inserting Glen Davis halfway through the fourth. There was no way Rivers wasn't going to give O'Neal, who hit all six of his shots and had 12 points, four rebounds and four blocks, some critical minutes in the stretch.

"Jermaine was huge," Davis said. "He did some incredible things out there. That's what we've been missing all year as far as blocking shots, and the little jump shots he hit were all money for us. So to have him is a plus because today I didn't have a big game and he stepped up.

"You've got the Big Three who are going to be there, getting the majority of the shots. But there's that one guy who always changes the game, and that was Jermaine today."

O'Neal's scrappy play seemed to come out of nowhere for the Celtics, who needed that kind of game from him with the other O'Neal -- Shaquille -- still out with a right calf injury. Jermaine has battled assorted ailments all season, but a left knee injury nagged him most, requiring Feb. 4 arthroscopic surgery.

The 15-year veteran appeared in only 24 games in his first season in Boston and averaged a modest 5.4 points and 3.7 rebounds, by far his lowest numbers in 12 seasons. But he played in all but two of the Celtics' last nine games and proclaimed he's finally healthy, just in time to stick it to the Knicks.

"Now is the first time all year that I've been able to play without any pain, any soreness, not being medicated to the point where it's affecting how I feel out there,'' O'Neal said. "So defense is something I really focused on. I know guys really depend on me to do that. I look at it as trying to be a safety in the back.

"You see the play develop, and altering a shot is just as good as blocking the shot. Taking a charge is a great possession-changer. Those things happened well for me tonight. But should you be happy with just one good game or do you continue to work? For me, I've got to continue to work."