Ray Allen didn’t approach Game 5 against the Heat any differently than the rest of the games.

He arrived at TD Garden at 2:45 in the afternoon, just over four hours before tipoff. He followed his usual game-day routine — change clothes, stretch, shoot. Nothing more, nothing less.

Even though he had uncharacteristically missed two critical free throws in Sunday’s Game 4 loss to the Heat, Allen didn’t let the slip-ups alter his strict pregame regimen.

But that doesn’t mean they weren’t on his mind.

“I’ll be honest — I did think about it,” he said of the two missed attempts, which could have cut the Celtics' deficit to two with 1:50 left. “I’m human. Because I missed the last free throw, I took in the game, I went to the free throw line and I just said to myself, ‘Just go through your routine. Just do what you do.’ You just have to always see it go through the hoop, no matter what you do. Just let it go through the hoop.”

On Tuesday night, Allen was locked in on the basket, thanks in part to the memory of the ball going out of it.

He scored a team-high 24 in the Celtics 96-86 elimination victory over the Heat. After posting just four points in 20 minutes of first-half action, he exploded for 20 in 20 minutes in the second half. Allen shot 5-for-6 from behind the arc and 9-for-15 from the field. He also was 1-for-1 at the line — on par with his 91.3 percent regular-season average.

On the defensive end, Allen helped his teammates contain the Heat’s deadliest weapon. Dwyane Wade shot just 2-for-7 from 3-point range.

“Ray is a human conditioner, I would say,” teammate Glen Davis said. “His condition is like crazy. To play defense on Wade, and then all of a sudden to run off screens and hit shots, I don’t even think he’s human. He’s different.”

Different, or just determined? Missed free throws in any situation, whether they impact the final result or not, can linger. But it’s what a player does with that frustration that sets them apart.

“Just go in the gym and just do it 'til your hands bleed,” Allen said. “Sometimes they do, because you’re holding the ball so much it splits your nail just from dribbling. You catch the ball and just keep shooting, and then I think at some point you become numb to it and it’s second nature.

“You just close your eyes and do it.”