ATLANTA — Avery Bradley limped into the locker room with his right hamstring heavily wrapped in medical tape. The Celtics guard stopped and put his right arm around a staff member, who helped him stay upright as he dressed.

Trainer Ed Lacerte walked over to Bradley, said something quietly to him and handed him one black crutch. Before using it, though, Bradley sat down as another staff member helped him put on his socks.

The Celtics’ 102-101 loss in Game 1 of their first-round playoff series Saturday night against the Hawks was a tough beginning, but it is also one they have plenty of time to overcome. If Bradley is sidelined for a significant period, though, the task will become considerably more difficult.

Coach Brad Stevens said Bradley “heard a pop’’ when he landed after trying to block Jeff Teague’s shot with seven minutes left in the game. When asked about that afterward, though, Bradley declined to talk about it. He was officially diagnosed with a right hamstring strain, and he said he would get an MRI Sunday morning.

“I just want to try to get treatment,’’ Bradley said, “and take it day by day.’’

Bradley’s injury came just as the Celtics were mounting yet another furious comeback from yet another sizable deficit. This time they’d trailed by 19 points before surging back. Seconds after Bradley was hurt, Jae Crowder hit a 3-pointer to give the Celtics their first lead, 83-80.

Bradley left the court moments later and did not return, and the Celtics were unable to hold on without him.

“We can’t tire ourselves out by digging a hole,’’ guard Evan Turner said. “We pushed ourselves back in the third quarter, and in the fourth quarter some people ran on [empty] obviously, but we need to help ourselves better.’’

It is true that this loss could be encouraging for the Celtics. They lost by just 1 point on the road despite shooting just 36.3 percent from the field, despite not having a fast-break point in the entire first half, despite falling behind by 19 points.

But it is also true they probably did not withstand Atlanta’s best shot, either. Forward Kyle Korver, one of the most dependable shooters in the league, missed all seven of his 3-point attempts. He has only shot that poorly in 4 of 964 career regular-season games. The Hawks made just 5 of 27 3-pointers overall (18.5 percent), yet they are the team that will go into Tuesday night with a 1-0 series lead.

“I think we just made one or two more plays down the stretch,’’ Atlanta coach Mike Budenholzer said. “And we need to be better.’’

In the days leading up to this series, both teams were asked about all their similarities. They are two tough, defensive-minded groups that force turnovers and generally are a menace. There was every reason to believe this would be a tense, taut series. And if Game 1 was any indication, it will be.

The Hawks led, 96-91, with 1:33 left when Celtics forward Jonas Jerebko missed an open 3-pointer that could have pulled Boston within 2. But at the other end, Marcus Smart came up with a steal and then cleaned up Turner’s missed layup, pulling the Celtics within 96-93.

Korver missed a 20-footer and Smart gathered the rebound with 45.7 seconds left. After a timeout, though, Turner, a 24.1 percent 3-point shooter, missed one from the top of the key with 38.9 seconds left.

The Celtics did not need to foul, as they had time to get a stop and then mount a quick counterattack. But Smart hacked Kent Bazemore, who hit a pair of free throws.

“I was just trying to get back and didn’t know the time,’’ Smart said. “I wasn’t really paying attention to it. Last time I checked I thought the time was lower than 24, but I made a costly mistake.’’

A 3-pointer by Crowder with 5.2 seconds left pulled the Celtics within 100-98, but they could not get a steal on the ensuing inbounds pass. After a pair of free throws by Teague, Isaiah Thomas hit a 3-pointer with 0.4 seconds left to make it 102-101, but the Celtics ran out of time. Still, Stevens was encouraged and upbeat after the loss.

“We’ve just got to shoot confidently and make some shots,’’ he said. “And I think we will.’’

Thomas finished with 27 points and eight assists to lead the Celtics. Al Horford paced the Hawks with 24 points and 12 rebounds.

The Celtics were mostly undone by a challenging first half in which they shot just 23.1 percent from the field, made 2 of 16 3-pointers, and did not have a fast-break point. Starters Crowder, Bradley, and Thomas combined to miss all 11 of their 3-point attempts in the half. Quiet starts have been somewhat common this season, and the Celtics know they are running out of time to patch up that issue.

Now they have two days to review film and practice and hope for the best regarding Bradley.

“I’m not worried at all,’’ Bradley said. “I have faith.’’

Adam Himmelsbach can be reached at adam.himmelsbach@globe.com. Follow him on Twitter @adamhimmelsbach.