BOSTON — There was the potential for turnabout in this series, and Celtics coach Doc Rivers knew it.

The Hawks seemingly had no chance in Game 3 at Boston. Their top three big men watched from the sidelines with injuries, and the fans at TD Garden gathered for the expected sacrifice.

It was the same situation the Hawks faced when Boston was without suspended guard Rajon Rondo for Game 2 on Tuesday in Atlanta — and won anyway.

“The guys have to go out and play and at the end of the day you hope they understand these are playoff games and you can’t give any away,” Rivers said before Game 3.

The Hawks tried to take it away from the Celtics. They shook off their depleted roster, scrapped well enough to force overtime, but eventually faded in a 90-84 loss.

Boston leads the best-of-seven series 2-1 with Game 4 on Sunday in Boston. If the Hawks lose that game, they will head back to Atlanta for Game 5 on Tuesday facing elimination.

The Hawks tried to steal Game 3 with defensive intensity, key contributions from role players and big shots late. The Celtics ran to an 86-82 lead in the extra period and held on for the victory.

The Celtics squandered an 80-72 lead with less than three minutes remaining in regulation. Willie Green made a 3-pointer, Joe Johnson sank a step-back jumper and then Johnson’s deep 3-pointer tied the score 80-80 with 1:23 to play in regulation.

Each team missed twice, setting up a final chance for the Celtics to win in regulation. But Paul Pierce missed at the buzzer under pressure from Johnson and Boston needed overtime to win.

The Hawks nearly earned the victory despite missing two of their three best players.

Forward Josh Smith was out because of a sprained left knee he suffered in Game 2. He had been their best player in the series and his injury further eroded Atlanta’s frontcourt depth.

Center Al Horford, a two-time All-Star, hasn’t played in the series. Neither has center Zaza Pachulia, who filled in admirably for Horford when he went down with a pectoral injury 11 games into the season.

That left Hawks coach Larry Drew to use lineups that featured swingman Tracy McGrady at power forward and small forward Marvin Williams at center. Center Erick Dampier, who had played in two games since March 18, joined the rotation.

The Hawks vowed to give the Celtics a fight, anyway.

“We have just got to try to out-will them,” Johnson said before the game. “We’ve got to find a way. We can’t dwell on or worry about what we don’t have. We have got to go for what we know.

“Is it going to be tough? Yeah, but it’s possible.”

After Atlanta played Boston tough in the first half, it looked as if Celtics fans might get the rout they wanted.

Boston opened the second half with a quick 8-4 spurt that featured six points on dunks or layups. The Celtics were running and the Garden, the crowd sensing the shift, was rocking.

But Drew called a timeout, and the Hawks settled down and had their best offensive stretch since early in Game 1. Center Erick Dampier started it with a dunk, and Johnson scored seven of the Hawks’ next nine points, capping the spurt with a step-back jump shot for a 53-52 lead.

The Hawks, who have been touched by injuries all season, couldn’t even make it to halftime without another player going down.

McGrady appeared to twist his ankle after a 3-point attempt in the second quarter. He writhed on the floor in pain before heading to the locker room, but came out to shoot jumpers at halftime and returned to play.

The Hawks caught a break because McGrady was providing the bench production they lacked in Games 1 and 2. He had 10 points and six rebounds in the first half to help the Hawks hold a lead early in the second quarter and trail just 40-38 at halftime.