Observations from the Celtics’ win over the Knicks

Celtics forward Daniel Theis is fouled by New York Knicks forward Marcus Morris during the second quarter.barry chin/globe staff/Globe Staff

Jayson Tatum’s 20-foot game-winner sent the Celtics to a 104-102 win over the Knicks on Friday night at TD Garden.

The Celtics took a 102-99 lead on a pair of Kemba Walker foul shots with 13.5 seconds left. The Knicks were out of timeouts and R.J. Barrett’s driving floater was long, but the ball ended up in the hands of former Celtic Marcus Morris, who drained a 3-pointer from the left arc with 4.7 seconds left, tying the score at 102.

After a timeout, Marcus Smart’s inbounds pass came to Jayson Tatum in the right corner. He spun and drilled a 20-foot fadeaway with 1.3 seconds left. New York was out of timeouts, and a baseball toss to the other end was batted away.

Tatum finished with 24 points.

Walker had 33 points to lead the Celtics and made all 14 of his free throws. According to the Celtics, Walker is the first Boston player to have at least 30 points, 6 rebounds, and 4 assists in three consecutive games since Paul Pierce did so in November 2002.

Morris had 29 points to lead the Knicks.

■  With 3:36 left and Boston leading just 92-91, Hayward’s pass was deflected out of bounds and initially ruled New York’s ball. Celtics coach Brad Stevens instantly called for a challenge, without even seeing a review. He was right, Boston got the ball back, and Walker drilled a big 3-pointer from the top of the key to stretch the lead to 4.

■  Yes, there were Tacko Fall chants during this official review. But in this case the fans were just chanting “Tacko” rather than “We want Tacko,” so maybe they just wanted to acknowledge the big man.

■  Smart started the game guarding the Knicks’ 6-foot-9-inch, 255-pound power forward Julius Randle. No rest for the weary after the 6-3 Smart tussled with 6-11 Bucks superstar Giannis Antetokounmpo two nights ago. Smart relishes these opportunities. In fairness, about 80 percent of New York’s roster is comprised of power forwards, so there aren’t many other options.

■  With Enes Kanter (knee) and Robert Williams (hip) out, the big Knicks had an even easier time scrapping for offensive rebounds. They held a 16-3 edge.

■  Tatum showed off his passing a bit in the first half, first while attacking the rim, and then on a nice no-look dish to a cutting Daniel Theis for a dunk. His game continues to evolve.

■  Stevens often talks about how a quick trip to the free throw line brings a real confidence boost for a player at the start of the game. Rookie Grant Williams took four foul shots soon after checking in in the first half, and he followed that up with a fast-break layup and a nice turnaround jumper.

■  As Knicks rookie R.J. Barrett sprinted upcourt on a fast-break, Smart was timing his steps as he readied for a blocked shot. Smart soared and stuffed Barrett in midair, but may have swiped his arm, too. The foul was called, and Smart was furious, and his reaction drew a technical foul. Smart went over to Stevens and appeared to talk with Stevens about challenging the call, but Stevens did not.

■  The Celtics’ bench missed all eight of its 3-point attempts. It’s been a tough start for rookies Grant Williams and Carsen Edwards, who are now a combined 2 for 21 from long range this season.

■  Walker’s ability to get to the free throw line continues to be a huge asset for Boston. One game after going 14 for 15 in a win over the Bucks, the point guard made 14 of 14.

■  Hayward continued his recent trend of quiet first halves followed by more impactful seconds. He had just 2 points on 1-of-5 shooting before the break before starting the third quarter with a pair of 3-pointers. He added a big one with 4:52 left in regulation that put the Celtics ahead, 90-88.

■  Morris got a nice yet slightly subdued reaction when he was introduced in the Knicks’ starting lineup. It was probably about the right level of noise for a player who was here for just two years.

■  Speaking of ovations, point guard Kemba Walker rightfully took over the honor as the last Celtic to be introduced this year. His ovations don’t come close to the ovations Kyrie Irving received when he was here, and to my ears they’re also noticeably quieter than Isaiah Thomas’s after he became an All-Star. But Walker is still new here. The guess here is they’ll just get louder and louder the more he shows Boston what he’s capable of doing.