Boston’s Derrick White, left, drives toward the basket as New Orleans guard CJ McCollum defends during Monday’s game in Boston. Steven Senne/Associated Press

BOSTON — The Celtics began the season unbeatable in TD Garden.

After back-to-back setbacks at home, they reminded New Orleans why they’ve been so tough to beat in their own building.

Jayson Tatum scored 12 of his 26 points in the fourth quarter and Boston rallied past the Pelicans 118-112 on Monday night.

The victory snapped a two-game skid at home for Boston, which opened 20-0 at TD Garden.

Jaylen Brown added 22 points and 11 rebounds. Jrue Holiday had 20 points and Derrick White finished with 17.

Celtics Coach Joe Mazzulla said he hopes that narrowly avoiding a third consecutive home loss will help rid the East’s top team of its sense of “entitlement” to win games.

“We can’t lose sight of the fact that we have to earn a win every night,” Mazzulla said.

Brown said he feels the team is learning from its shortcomings.

“It’s a full season. It’s a full body of work you have to account for night in and night out,” Brown said. “We don’t really make no excuses. But it’s tough. You’ve got to come out and be the best version of yourself every single night.”

The Pelicans led by 17 in the first half but were outscored 68-52 over the final two quarters to drop their third straight game.

Brandon Ingram led New Orleans with 28 points, seven rebounds and six assists. Zion Williamson finished with 26 points.

The Pelicans outscored the Celtics 58-44 in the paint but committed six of their 12 turnovers in the fourth quarter.

“We know our blind spots. We know that the last five minutes of a game we have to execute better and get quality looks,” Pelicans Coach Willie Green said. “We had a few turnovers down the stretch. That’s where we have to grow.”

In his second game back since sitting out with a bruised bone in his left foot, Williamson’s scoring and ability to slice through Boston’s interior defense helped New Orleans stay in front for most of the night.

The Celtics tightened things up defensively in the fourth quarter, turning back-to-back stops into a floating jumper and 3-pointer by White to cap a 13-3 run that tied the game at 94 with just over six minutes to play.

Two lead changes later, another 3 by White put Boston in front 99-98. That was followed by Tatum’s steal, which he punctuated with a two-handed dunk.

A free throw by Tatum and layup by White pushed the lead to 104-99.

Boston got it up to 109-103 when Tatum came up with another steal. He pushed the ball up the floor, found a lane and slid in for another dunk with 1:42 remaining.

Williamson said physically he feels he’s in a good spot at this point in the season.

“I’m just stacking my days,” he said. “It’s a slow grind. The team has been a big help with that. When the end of the season gets here, I feel like I’m going to be in an amazing spot for us to really do some real damage in the playoffs.”

A slow start doomed Boston during its 19-point loss to the Clippers on Saturday. The Celtics again came out sluggish against the Pelicans, quickly falling behind by 14 in the opening quarter.

New Orleans extended its lead to 17 in the second before a late Boston spurt cut it to 60-50 at halftime.

The Celtics needed less than three minutes of the third quarter to trim the deficit to two. Williamson responded by scoring the Pelicans’ next nine points over the next two-plus minutes to help keep New Orleans in front.

Boston surged again with a 9-2 run, capped by Sam Hauser’s 26-footer to give the Celtics their first lead since early in the first quarter.

But the Pelicans settled down and took an 87-81 edge into the final period.