The Boston Celtics were clinging to a one-point lead with little more than a minute to play in Tuesday's Game 5 of the Eastern Conference finals when Paul Pierce put the ball -- and maybe the game -- in his own hands. Isolated against LeBron James with the shot clock entering single digits, his coach wanted him to drive to the basket. Pierce had other ideas.

Pierce splashed a 25-foot contested 3-pointer from the left wing that put Boston on top by four with 52.9 seconds to play and propelled the Celtics to a 94-90 triumph over the Heat at American Airlines Arena.

"It's kind of hard to say in those situations, things are going so fast, you kind of play on instincts," Pierce said. "I saw (James) back up, he gave me a step. I knew it was within my range. The shot clock was winding down -- I just took a shot. That's just being in those moments so many times and understanding what your team needs and being able to concentrate and get the best shot for us.

"I thought that was the best shot. Once I saw him back up, then I was able to knock it down."

Truth be told, Celtics coach Doc Rivers was hoping Pierce would attack the basket, at least giving him an opportunity to get to the charity stripe if he couldn't get a bucket near the rim.

"I kind of wanted him to drive, honestly," Rivers admitted. "I've been around Paul long enough that, right when he got into the footwork, you knew he was going to shoot it. At least I did, because I've seen him enough. I didn't know if I wanted that shot. Honestly, I thought he was going to drive it, but he made it. That's what players like Paul do. It really is. He's a big shot maker, he always has been."

Pierce, who struggled with his shot early Tuesday, finished with 19 points on 6-of-19 shooting with 4 rebounds, 4 assists and 2 steals over 43 minutes. Afterward, Pierce was asked if he had any additional motivation after James helped end Boston's season in last year's Game 5 of the conference semifinals, but downplayed any revenge factor.

"Things that happened last year, happened last year -- you have no control over it," said Pierce. "This is a whole new ballclub. We came in with the right focus. That was the key for us coming into Game 5. I saw it in shootaround -- our focus. You could feel it. Doc always says in the locker room (that) he can feel it when we're locked in. It was one of those games where we were locked in."