John Collins had experienced this before, watching a Hawks lead dwindle down, down, down, a once-lopsided matchup going down to the wire.

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Early in the season, closing games while entering the fourth quarter with a lead had been the team’s Achilles heel. That has changed significantly under interim coach Nate McMillan, who took over March 1, but the 76ers closing a 26-point deficit down to two in the final minute brought the feeling back.

Thanks to five points by Collins in the final minute, and a clutch 3-pointer and pair of foul shots by Bogdan Bogdanovic (21 points, five assists, four rebounds, three turnovers), the Hawks escaped Game 1 of the Eastern Conference semifinals with a 128-124 win Sunday in Philadelphia.

They entered the fourth quarter with a 16-point lead and led by 17 with about five minutes to play. Game 2 of the best-of-seven series is set for Tuesday in Philadelphia before Games 3 and 4 are set for June 11 and 14 in Atlanta.

“Definitely one of the more nerve-wracking moments in my young NBA career,” Collins said. “We’ve just been in that situation so many, so many times. Just seeing it again and trying to do everything in my power and the team’s power to not let it happen… Obviously we have a lot of film to go over and a lot of things to smooth over before we go into the second game.”

With 41.4 seconds to play, Bogdanovic hit a huge 3-pointer (shushing the Wells Fargo Center crows afterward) to put the Hawks up six. Later, Collins, who finished with 21 points, four rebounds, two assists, two steals and two turnovers, made two free throws after Joel Embiid (game-high 39 points, nine rebounds, three blocks, four turnovers) was called for a clear-path foul. He made both, then Trae Young (team-high 35 points and 10 assists) connected with Collins on an alley-oop.

Bogdanovic turned the ball over and a dunk by Ben Simmons (17 points, 10 assists, four steals, five turnovers) had the deficit back down to two. But, Bogdanovic recovered and, with the game on the line, made two free throws to close out the win.

“You definitely love to teach off of a ‘W,’ ” McMillan said. “We were able to get this first game. I think that’s really big, especially for a young team to get confidence. Certainly out on the road. We were able to do that tonight, but we know we’re going to have to be sharper going down the stretch and I expect us to do that.”

In an insane first half, the Hawks led by as much as 26 as they hit a franchise playoff record 13 3′s and had a franchise playoff record 74 points. The Sixers had nine early turnovers and were completely out of sorts, but settled down to find a rhythm as the game wore on.

The Hawks shooting 56.5% from 3-point range in the first half was obviously unsustainable, but they wouldn’t have crashed down to earth so hard in the second half if it weren’t for turnovers of their own adding up throughout the game.

They had two turnovers in the first quarter, seven in the second, two in the third and six in the fourth (that’s 17 total, compared to the 76ers’ 19).

“We talked about it and we expected them to play very aggressive,” Bogdanovic said of Philadelphia forcing turnovers in the second half. “They were down. And we did not play the way we wanted, the second half especially. We had a couple open shots that we missed, we had a couple turnovers, consecutive turnovers, that truly hurt us in the end. But now it doesn’t matter… We closed the game and we found a way to win.”

Hawks vs. 76ers

Game 1 - Hawks 128, 76ers 124

Tuesday, June 8: Game 2 - Hawks at 76ers, 7 p.m., TNT

Friday, June 11: Game 3 - 76ers at Hawks, 7:30 p.m., ESPN

Monday, June 14: Game 4 - 76ers at Hawks, TBD, TNT

Wednesday, June 16: Game 5* - Hawks at 76ers, TBD, TNT

Friday, June 18: Game 6* - 76ers at Hawks, TBD, ESPN

Sunday, June 20: Game 7* - Hawks at 76ers, TBD, TBD

* - If necessary