It was as if something had clicked in Avery Bradley’s head and body at the same time.

The player that was deemed as “The Savior” on the defensive end at the beginning of the season looked lost in the first five games, and the first three quarters last night, of this first-round series with the New York Knicks. He played like he had lost his way, like he had lost his identity, until the Celtics looked like theirs was gone as well.

But in a burst, the player that had made a name around the league as one of the best perimeter defenders returned — and so did the rest of his team.

The Celtics third-year guard spurred a furious fourth quarter comeback that ultimately fell short in the season-ending 88-80 loss to the Knicks in Game 6 at the Garden.

Bradley was 0-for-7 in the first three quarters with no steals, but sprung out of a slumber with 10 points and three steals in the final 12 minutes of play — the most production he’s had since Game 1.

“We just didn’t give up,” Bradley said. “We kept fighting and even though we were down by 20, we still felt like we had a chance.”

The Celtics weren’t down 20. They were down 26 with 9:49 left in the game when Bradley checked back in. He hit a 23-footer and then his defense started to take over the ballgame. The aggressiveness he displayed on the defensive end translated to his offense when he took Tyson Chandler to the hoop along the baseline and somehow scored over the Knicks 7-footer.

Then he picked Carmelo Anthony’s pocket cleanly at halfcourt, ran down and soared with a two-handed stuff to cut the lead to four with 3:32 left in the game.

It was at that point, somewhere in the few dribbles he had in transition or in the second he was rising toward the rim, that he thought the Celtics were going to win and force a Game 7.