With the Celtics clinging to a two-point lead late in overtime, Tatum carved through the lane and was met by three defenders. Springer was alone in the right corner, and that was no accident. The guard was 0 for 4 from beyond the arc this season and 1 for 5 in this game. But Tatum fired a pass Springer’s way, and he hit the shot to help put the final touches on a 117-113 win against this severely shorthanded Clippers team.

“That was big, man,” Springer said. “Shout-out JT for throwing me the rock in that corner.”

But Springer’s more significant impact came earlier. Kevin Porter Jr. was having his way with the Celtics in the third quarter. His 3-pointer with 5:01 left gave the Clippers a 78-75 lead and made him 6 for 6 from the field in the period.

Springer checked in for the first time a minute later and coach Joe Mazzulla challenged him to change the temperature with his physicality.

“He told me to just go out there, lock up, and cause havoc,” Springer said.

He mostly bottled up Porter the rest of the way, bumping and swiping and annoying the Clippers guard. He said he could sense his frustration.

Porter Jr. had 24 points on 11 of 16 shooting at the time but went just 1 for 5 and scored 2 more points after that, with Springer serving as his primary defender.

Springer, who had not played more than 13 minutes in a game all season, was on the floor for 20 of the final 21 on Wednesday and tied his career high with four steals.

“You never know when you’re going to play,” Tatum said. “Game’s not going the way it’s supposed to or we expect. Joe calls your number to come and shut somebody down and give us a spark off the bench, and he did that.”

The Clippers are in a grueling stretch that includes four games in five days, so they appeared to essentially concede Wednesday’s game in order to ensure that their long-term goals were not disturbed.

They ruled out their four leading scorers: forward Kawhi Leonard, point guard James Harden, center Ivica Zubac, and guard Norman Powell, as well as rotation players Kris Dunn and Nicolas Batum.

The Celtics, who were playing the first game of a back-to-back set, were to be without Al Horford and Jrue Holiday. After the Clippers’ long list of absences was revealed, Kristaps Porzingis was ruled out with an illness even though he was seen going through a full workout at the team’s morning shootaround.

But the Clippers’ backups pushed Boston to the brink of an unsettling loss. Los Angeles led by as many as six points in the fourth quarter before surrendering all of that lead. Then the Celtics’ late-game execution issues resurfaced.

They had the ball and a 103-99 advantage with 22 seconds left before going through a grisly stretch that was reminiscent of last week’s loss to the Hawks. Jaylen Brown committed an offensive foul and Amir Coffey capitalized with a dunk with 12.7 seconds to play.

After a timeout, the Clippers trapped Brown near the baseline and he threw the ball away, leading to a Derrick Jones Jr. layup that tied the score at 103 with 4.4 seconds left. The Clippers then trapped Tatum, and Derrick White’s 3-pointer from the left arc was blocked by Jones Jr., forcing overtime.

“I got some different coverages the Clippers were throwing at us,” Brown said. “They did a good job of trapping us in the corner and stuff and they made the game closer than it probably should’ve been. We just got to be better.”

The Celtics started the extra session how they probably wished they had ended regulation, with 3-pointers by Tatum, White, and Brown staking them to a 112-105 lead.

The Clippers pushed back and pulled within 112-110 on a Jones Jr. 3-pointer with 56.9 seconds left. Los Angeles looked to trap Tatum and Brown and force someone else to damage them, and Tatum willingly found Springer, whose 3-pointer from the right corner made it 115-110 with 34.3 seconds to play.

“Basketball is about making reads, the right reads,” Tatum said. “They left him open, the guy in the corner. You’ve got to make the right play, and he stepped up big-time tonight.”

Still, Amir Coffey answered with a quick-strike 3-point play to make it 115-113. The Celtics responded with a patient offensive possession that ended with White finding Neemias Queta for a layup with 5.6 seconds left, and Boston survived.

Brown had 25 points to lead the Celtics and Tatum added 24 points, 8 assists, and 7 rebounds. Springer registered 8 points to go with his 4 steals.

Jones Jr. had 29 points to lead the Clippers, who were undone by 23 turnovers, including 11 in the third quarter.