When Kristaps Porzingis went down early with an eye injury on Saturday night in Indianapolis, it spelled some trouble for the Celtics. Porzingis is the new key to Boston’s engine, and they clearly missed him the last time they were in this building last month, when they lost to the Pacers in the In-Season Tournament.

But the Celtics still have Jayson Tatum, and their strengths lie not only in their depth but their ability to adapt and overcome unforeseen challenges when the game isn’t unfolding exactly as expected.

The Celtics played with some fire on Saturday night. They led wire-to-wire, but let the Pacers hang around because they committed too many turnovers, finishing with 18 of them, and some bizarre shooting at the free-throw line. But they stayed in control. They had an answer to every Pacers run, and then buried them with a strong finish to grab an impressive 118-101 victory.

Tatum scored 38 points, including eight 3-pointers and 15 fourth-quarter points, with 14 rebounds and six assists, Jaylen Brown had 31 points, and the Celtics received major contributions down the stretch from others in the absence of Porzingis, including Al Horford and Oshae Brissett. Boston’s defense shined in the fourth quarter as they limited Tyrese Haliburton and the league’s best offense. A night after the Pacers recorded an obscene 50 assists for 150 points, the Celtics held them to a season-low 101 points.

The Celtics were fortunate that the Pacers missed a lot of open looks as they went 8-for-42 from deep, but aside from a few runs, never let the hosts get into a real rhythm. Haliburton, who torched the C’s last month, finished with just 17 points and seven assists.

The C’s, who led by as many as 16 in the first half, allowed the Pacers to get within two twice in the third quarter. After not attempting a single free throw in the first half, the Celtics somehow missed three of their first 11 attempts at the line in the third quarter. Tatum and Derrick White were mired in some foul trouble, and were on the bench for most of the period. But the C’s brushed off every Pacers run and never lost the lead.

Then, Tatum took over. An early 3-pointer in the fourth ignited a 14-2 run, and the Celtics never looked back. Brissett, who had five offensive rebounds, scored a three-point play. Tatum then converted a three-point play, then after a White block of Haliburton, buried another pull-up 3-pointer to put the C’s up 15.

With Porzingis out because of his eye injury, a fresh Horford – who rested in Friday night’s win over the Jazz – helped bring the Celtics home. He blocked Haliburton at the rim. Moments later, he perfectly read a Haliburton pass and deflected it for a steal, then found Brown for an alley-oop in transition. He then found Brissett for a 3-pointer for his eighth assist of the night that put the Celtics up 16, and effectively sealed the victory.