BOSTON – Pat Riley sat 20 rows behind the Miami Heat bench on Monday, living and dying with every possession.

Riley always carries himself like the coolest guy in the building whether it’s pitching South Beach to LeBron James in an Ohio office building in July or watching the team he built attempt to end an 11-game losing streak in a hostile environment in Boston.

On Monday, Riley occasionally shook his head or mumbled a few words. But it wasn’t until Dwyane Wade’s off-balance jumper gave the Heat a six-point lead in overtime that Riley showed his true emotions. The Hall of Fame coach and current president of the Miami Heat stood and cheered before turning to his boss, Heat owner Micky Arison, and smiling.

Riley, the winner of the NBA’s wild free-agent summer, is inching closer to being a winner again where it really counts. The Heat can advance to the Eastern finals and perhaps end the Celtics’ reign as the class team of the conference with one more victory, starting Wednesday night with Game 5 in Miami.

It will take nine more wins to capture a championship and, should Miami reach that goal, the organization may well look back at Game 4 in Boston as the night the Heat became a championship-caliber team.

“Me and LeBron talked about this (Sunday) night at dinner, this being the biggest game for us since 2006 and 2007 when he was playing against Detroit and I played in the Finals,” Wade said after Miami defeated Boston, 98-90, in overtime. “We had to approach it that way. It was personally just a challenge to myself, LeBron and Chris (Bosh) to lead the way. It was on us to lead the way and get a win.”

Riley’s signature move, signing James, is paying immediate dividends. James had 35 points and 14 rebounds as Miami took a 3-1 series lead. He also seemed to momentarily quiet the criticism of not being a clutch player.

Yes, a James turnover gave Boston a chance to win in regulation, a miscue that could have haunted him all summer. But James’ defense on Paul Pierce forced the Celtics small forward to take poor shot as time expired.

Plus, James was responsible for tying the game with two minutes left in the fourth quarter by hitting a contested three-pointer in front of the Boston bench just after Ray Allen had done the same in front of Miami’s bench.

“The only way to redeem myself for turning it over was for me to get a stop and give us an opportunity to win,” he said. “I had a timeout to kick myself. I had to let it go.”

For now, LeBron James, Wade and Bosh have figured out how to play together. The trio scored 83 of Miami’s 98 points, including 28 of the last 29. Bosh recovered from a nightmarish 1-for-6 shooting performance in Game 3 to score 20 points in Game 4, including a tap-in with 24 seconds remaining in OT that gave Miami a five-point lead.

The Celtics’ inability to score over the last 17 minutes was downright shocking. They scored 17 points in the fourth quarter and overtime and their top four players - Pierce, Kevin Garnett, Ray Allen and Rajon Rondo - shot a combined 20-for-49 including Garnett’s 1-for-10.

The Celtics played their best basketball of the playoffs on the road by winning Game’s 3 & 4 in New York. In order to get the series back to Boston, they’ll have to win Game 5 Wednesday night Miami and in order to advance they’ll have to win two more road games.

Otherwise, the Celtics could be facing a summer of change. Doc Rivers is expected to step down as head coach. They’ll still have the talent to remain a playoff team but their aging roster may never again be good enough to beat the Riley’s team.