MIAMI, March 25 (Ticker) -- Erick Strickland may have sealed the fate of the Miami Heat.

Strickland scored a season-high 23 points and nailed a huge 3-pointer in the final minute as the Boston Celtics posted an 87-82 victory over the Heat, whose playoff hopes were dealt a crippling blow.

Miami has recovered from a terrible start to get back in the playoff hunt but had lost three of its previous four games with just 14 remaining.

"I don't care about the standings, my main concern is for us to start winning," Miami center Alonzo Mourning said. "If we start winning, the standings will take care of themselves."

The Heat contained the Celtics' potent combination of Paul Pierce and Antoine Walker but were done in by the team's sixth-leading scorer.

NBA TV highlights from Celtics-Heat: 56k | 300k The Heat held Paul Pierce to 19 points, almost seven below his average, but still lost. Victor Baldizon/NBAE/Getty Images

Averaging just 7.2 points per game, Strickland scored 10 in the final six minutes. He made 6-of-14 shots and grabbed six rebounds off the bench.

"He really played very well, played within himself," Boston coach Jim O'Brien said. "We talked to him at halftime and said, 'You're a hell of a shooter, we're just going to keep giving you the basketball. When you're open you're going to knock them down.' He made some big shots for us."

The teams were tied three times and traded the lead four times before Walker made a jumper to put Boston ahead for good, 74-73, with 4:53 left.

After Tony Battie made a hook shot, Strickland buried a 3-pointer for 79-73 cushion with 2:07 remaining. But Jimmy Jackson responded with a 3-pointer and Mourning added two free throws to cut the deficit to one point with 76 seconds to go.

Strickland made a driving layup and, after Jackson sank two free throws, buried another 3-pointer to give Boston an 84-80 edge at 24 seconds.

"It's a really big shot, just a big swing late in the game," Strickland said. "It gives you a lot more confidence. It makes them a lot tighter coming down for their shot. The whole team, they just kept telling me 'Shoot the ball. If you've got the shot, take it.' They stayed confident in me."

"The game was an 81-80 game and they let one go that went in," Miami coach Pat Riley said. "I thought Erick Strickland did a great job. He scored 10 in the last six minutes and hit two threes for them."

Strickland sealed the victory with a pair of free throws eight seconds later and Pierce added 1-of-2 with nine seconds to play.

Pierce had 19 points and Walker 17 for the Celtics, who are in third place in the Eastern Conference, 1 1/2 games ahead of Milwaukee.

Mourning collected 20 points and 10 rebounds and Eddie Jones scored 19 points for Miami, which fell four games behind Indiana for the final playoff spot in the East.

"I believe in them," Riley said. "As much of a daunting task as this is, don't ever count yourself out until the numbers say you are out."

"We aren't quitting, we don't have any quit in us," Jones added. "If we did, at 5-23 we would've quit. We had a tough night tonight, we just need to bounce back. We are taking this game-by-game."

The Heat's loss allowed the New Jersey Nets to become the first team in the Eastern Conference to clinch a playoff berth.

Jackson finished with 12 points and nine rebounds and Brian Grant added eight and 12 for Miami, which shot just 38 percent (26-of-68) and committed 21 turnovers leading to 22 points for Boston.

The Celtics shot just under 38 percent (29-of-77) but had just 10 turnovers despite playing without point guard Kenny Anderson, who was placed on the injured list Monday.

Miami jumped out to a 14-4 lead less than six minutes into the game, but Boston scored seven of the next eight points to pull within 15-11. The Heat had a 23-16 edge 71 seconds into the second period before Pierce scored six points during a 7-0 run and tied it with a layup with 8:02 to go.

There were 15 ties and 14 lead chances before Walker's jumper gave the Celtics the lead for good with 4:52 remaining.