Boston ? Red Auerbach has witnessed all of the Celtics’ great moments, all of the great games and stirring finishes. On Saturday, even the coaching legend could hardly believe his eyes.

Auerbach sat in his usual courtside seat and watched the Celtics overcome the largest third quarter deficit in NBA history, wiping out New Jersey’s 21-point lead to grab an improbable 94-90 win.

“I give the guys credit, especially Jimmy O’Brien,” Auerbach said in a joy-filled Celtics locker room. “The way we were playing, geez. We were so bad, I probably would have gotten thrown out.”

Auerbach said this Celtics team has impressed him with its resiliency and toughness in tight games.

“They don’t give up,” he said. “Paul (Pierce) was struggling and he just played great in the fourth quarter. Antoine (Walker) is always there.”

Three Celtics said they’ve played in a similar shocking comeback win. Walker, Tony Delk and Walter McCarty were part of a Kentucky team that wiped out a 20-point deficit at LSU, a comeback that Delk says he’ll always remember.

“But this one, wow,” he said. “Playoffs, at home. It doesn’t get much better.”

Like Auerbach, Delk said these Celtics seem to play better with their backs against the wall.

“We’ve played better when we’re down,” said Delk, who had seven points and five rebounds off the bench. “We put pressure on them and forced them to make shots, and they couldn’t do it.”

The Celtics ran through a love-hate-love day with the sellout (18,624) crowd at the FleetCenter. The crowd was elated at the start, happy to be part of a playoff atmosphere that’s made longtime Celtics watchers remember the old Boston Garden days.

But New Jersey’s impressive, dominating start through the first half quieted the crowd. By halftime, the fans were booing the home team.

More boos rained down in the third quarter, but the fourth quarter was a different story. As the team showed life, so did the fans. Then the crowd became part of the comeback. New Jersey had a major problem being heard when plays were called out, and as the Celtics stormed to the lead, the crowd could not contain itself.

O’Brien said the day will be another installment in Boston’s new-found love affair with this group of Celtics.

“It’s so impressive to be in a building when nobody leaves. A team is down 26 and nobody is leaving,” the coach said. “It was just a great, great thing to see.”

Byron Scott has many remembrances of Boston, some sour, some sweet. The Nets’ coach recalls wins as a member of the Laker teams of the 1980s and so many trips into the old Boston Garden.

“I miss some of them, but I don’t miss this one,” he said when asked about the now extinct older NBA arenas. “This (FleetCenter) is plush compared to the locker room we had to deal with in the ’80s. This has air conditioning, hot water, lots of space.”

Scott said that when he learned that the Nets and Celtics will play on Memorial Day, one particular Memorial Day game in Boston came rushing back to him. The Celtics whacked the Lakers in Game 1 of the 1985 Finals, 148-114, a game that came to be called the “Memorial Day Massacre.” But Scott reminded everyone that the Lakers bounced back to win that series, 4-2.