Paul Pierce delivers at closing time

BOSTON -- His ailing left knee might as well have been a bull's-eye, as the Atlanta Hawks were not skittish in going right at Paul Pierce during Thursday's Game 6 of an Eastern Conference first-round series at TD Garden.

Sure enough, down two with less than 10 seconds to play, the Hawks put the ball in the hands of Joe Johnson, who drove on Pierce.

You almost could have forgiven Boston's captain if he let Johnson blow by him, finish at the rim and tie the game. But even as the Hawks spread the floor for isolation, Pierce still managed to drag that bum knee -- 40 minutes logged to that point -- straight to the blocks and swatted Johnson as he went up for a layup.

Moments later, Pierce was at the other end of the court at the free throw line, sealing an 83-80 triumph that ousted the Hawks from the postseason and pushed Boston through to a conference semifinal series against the Philadelphia 76ers.

"Paul, he's a gamer," said Celtics coach Doc Rivers. "That's what he is."

After the team's morning shootaround on Thursday, the Celtics took the unusual move of clarifying that Pierce has a sprained MCL in his left knee, essentially confirming that he has a partial tear, but one that he's trying to play through this postseason.

A few hours later, Rivers admitted the injury has the potential to get worse and said he wasn't sure how the team would compensate if Pierce struggled as much as he did in a Game 5 loss Tuesday in Atlanta.

Yet with Boston facing what amounted to a must-win situation -- the Celtics did not want to head back to Atlanta for a deciding Game 7 -- Pierce loaded up his knees with some extra padding and support, then played a team-high 40 minutes, 12 seconds while chipping in 18 points, seven assists and five rebounds.

Sure, Pierce had a little more hop in his step than he did on Tuesday night, but he was clearly still hobbled. Alas, it's going to take more than a bum knee to get him off the floor.

Asked how he felt after Thursday's game, Pierce admitted he was "a little tired and sore."

"I played a lot of minutes, had to guard one of the toughest one-on-one players in the league [Johnson] all night," he added. "That's the nature of this beast. You've got to be ready to bounce back Saturday -- one day of play, one day of rest -- you know this is it. We might never have this opportunity again."

Yes, Pierce got a little bit nostalgic after watching Kevin Garnett put the Celtics on his back, registering game highs with 28 points and 14 rebounds to carry the team in a Game 6 in which his Big Three brethren were clearly ailing.

Despite the bad knee, Pierce gave the Celtics an early spark, scoring 12 first-half points on 4-of-6 shooting. Coming out of the intermission, he simply didn't have it, however, and missed 4 of 5 shots in the second half.

As he is wont to do, Pierce simply morphed his game to compensate. He became a distributor at times, handing out five second-half assists while leaving the floor for a mere 2:19.

And when the Celtics needed vintage Pierce, he gave it to them.

With Boston down 79-76 with just more than two minutes to go, Pierce came off a pick-and-roll with Garnett and, despite a double-team of Johnson and Josh Smith hounding him, found another gear to turn the corner and attack from the left baseline. Pierce hopped to the circle and used the rim for protection while sneaking in a layup with Smith draped all over him, Pierce's headband going flying from the contact.

But it was Pierce's defense on Johnson that might have ultimately saved Boston.

"It's funny, right before halftime, I thought [Pierce] guarded [Johnson] as well as you can, and he made [a couple of shots]," said Rivers. "Joe Johnson is a shot-maker. And it's exhausting. You're on the bum leg, you're guarding their best player and we need you to score."

Pierce did it all. And even though there were times when you couldn't help but wonder if he was a liability on the floor, the Hawks couldn't take advantage of his limited mobility when it mattered.

As usual, Pierce stepped up his game in key moments.

He's done it before. And because he doesn't know how long he'll get to do it with this core, he's savoring these types of performances.

"Like I said, we're playing like this is it," said Pierce. "This could be our last chance together, so we're going to give it one last run and see what happens."

Pierce can't predict the future, but it's not hard to predict that good things happen when he's on the floor in big-time situations. He proved it again on Thursday.