BOSTON — What looked like an easy day for the Boston Celtics turned into a fight to the finish Saturday.

It’s something they’ve got to clean up heading into the postseason.

Kyrie Irving just missed his second straight triple-double with 30 points, 11 rebounds and nine assists, Jaylen Brown scored 23 points with a key 3-pointer and the Celtics held off the Atlanta Hawks 129-120 after blowing a 25-point second-half lead.

“To be mature about having the lead, you’ve got to keep the pressure on them and keep playing smart basketball on both ends of the floor,” Irving said. “We didn’t do that.”

Marcus Morris had 19 points and Jayson Tatum 18 for Boston, which has won 6 of 8.

Trae Young led the Hawks with 26 points, John Collins scored 20 with 11 rebounds, Taurean Price had 17 points and Vince Carter scored 16.

Irving had his second career triple-double Thursday in a win over Sacramento.

It could have been a costly victory for the Celtics: Gordon Hayward suffered a strained neck early in the game and didn’t return. Hayward banged his head into the shoulder of John Collins of Atlanta, who was setting a screen, and looked dazed before going to the locker room.

Coach Brad Stevens said Hayward was “woozy” and sent home after halftime.

After Boston squandered the 25-point lead, Brown nailed his 3 from the right corner, sparking a 9-0 spurt that gave the Celtics a 121-112 edge with three minutes left.

“It’s just making sure we keep our focus throughout even when the game is supposed to be out of reach,” Al Horford said. “This proves any team can get into it.”

Boston blew big leads in consecutive home losses against the Los Angeles Lakers and Clippers early last month.

The Celtics held their large lead late in the third but got just one basket in seven minutes – a three-point play by Tatum – when the Hawks outscored them 28-6 to cut it to 109-106 on Young’s 3-pointer with 7:25 to play.

“It’s maddening because what happened in the end of the third, early fourth, was they ratcheted up their pressure and we were on our heels, and you could see it,” Stevens said.

Atlanta made it 112-112 on Kent Bazemore’s two free throws.

“We’ve been doing that a lot throughout this year. We get down big, then we have to fight our way back into the game,” Young said. “I think what happened today was we ran out of gas.”

Boston led by 12 at halftime and went on a 15-3 run midway into the third to push its lead to 103-78 on Irving’s step-back 3-pointer.

But Atlanta had a 14-2 run to slice it to 105-92.

“To be down (25) in the third and to tie the ballgame up is a testament to the guys in that locker room – young, old, whatever you want to call them,” Hawks Coach Lloyd Pierce said.

The Celtics started hot and were shooting 66.7 percent late in the second quarter when they opened a 66-50 lead. They carried that into a 74-62 edge at intermission, matching their season high for points in a half.

SUNS 138, PELICANS 136: Josh Jackson hit a tying 3-pointer with two seconds left in overtime, the Pelicans were assessed a technical foul when they called a timeout they didn’t have, and Devin Booker hit the free throw to give Phoenix the lead for good at New Orleans.

WIZARDS 135, GRIZZLIES 128: Bradley Beal scored 40 points for the second straight night and Washington won at home.

NOTES

LAKERS: Forward Brandon Ingram is expected to be ready for next season after surgery on his right arm.