BOSTON — Kristaps Porzingis rode a stationary bike in the visitor’s locker room after this one — more energy displayed than the Knicks exhibited in a historically bad fourth quarter.
“It felt like in the fourth, they couldn’t miss and we couldn’t make a shot,’’ Porzingis said. “That’s how it felt.”
Kyrie Irving and Marcus Smart were out, the Celtics played four rookies in their rotation and Celtics coach Brad Stevens gave Terry Rozier his first career start.
It didn’t matter as the Knicks’ offense went comatose, scoring a record-tying-low eight points in the final period as the Celtics outclassed them in a 103-73 disgrace at TD Garden Wednesday. The Knicks shot 32.2 percent from the field with their three-guard starting unit combining to go 4-for-23.
Coach Jeff Hornacek said the Celtics are a grittier defensive bunch when Irving is absent.
“They’re a very good defensive team — even better when Kyrie’s not out there,’’ said Hornacek, whose club fell to 23-29. “They took advantage and got physical. They were just aggressive defensively and didn’t give us anything easy.”
The 30-point defeat was a spiritless performance on the second night of a back-to-back, as the Knicks tied their record for fourth-quarter futility in getting outscored 22-8.
While the Knicks guards didn’t take advantage of the Celtics’ depleted status, Rozier posted a triple-double (17, points 10 assists, 11 rebounds).
As the Knicks offense wore icicles, Hornacek wished their defensive grit would have been unleashed in the 53-28 second half.
“Nights you’re not hitting shots, lock in on the defensive end and win an 85-84 game,’’ Hornacek said. “We didn’t do that. We dropped our heads because we weren’t scoring.’’
Porzingis, who usually is defended by the physical guard Smart, quieted after a fast start, scoring just three of his 16 points after intermission in 34 minutes, shooting 7 of 18. He was also a rare victim of a poster dunk.
“Everybody was off — myself, I felt I missed so many good looks, great looks,’’ Porzingis said. “It was off night as a team shooting-wise. Obviously they’re one of the top defensive teams. They did a great job, but it was an off night for us.’’
“They have an identity. We’re trying to find one ourselves.”
Porzingis hasn’t excelled in back-to-backs this season, but Hornacek wouldn’t lay it on that.
“They put good pressure on him, challenged every shot,’’ Hornacek said.
During Porzingis’ 13-point half, he was the main character in a nasty poster dunk by Boston’s Brown. The Latvian was able to smile about that.
“Was a great dunk, especially against the top shot blocker in the league,’’ Porzingis said. “He should be in the dunk contest.’’
Brown slashed down the right side, leapt and powered one down on the face of Porzingis. Porzingis, who leads the NBA in shot blocking, was helpless to stop it. To his credit, Porzingis got one back, blocking a Brown drive in the third period with ease.
Tim Hardaway Jr. put forth his ugliest outing since his return from a stress reaction, scoring four points on 1-of-10 shooting. Courtney Lee had a quiet seven points (2 of 8) and starting point guard Jarrett Jack notched just two points (1 of 5).
“This team is a great ballclub,’’ Hardaway said. “When they don’t have Irving, they amp up their intensity level because they know.’’
The Celtics started the fourth quarter on an 18-2 run to go up by 32 points as the Knicks got worse as the night wore on.
“I don’t think we gave up, when things start to go bad, we need to set harder screens,’’ Hornacek said. “It snowballed on us because we weren’t making shots.’’
Porzingis’ Brown block didn’t spark the Knicks. Two possessions later, Brown snaked to the hole past Lee for a layup, and after a Michael Beasley brick, Marcus Morris hit from mid-range upping the lead to 76-60 with 2:37 left in the third quarter. It was downhill from there.
“They didn’t play like a young team today,’’ Hardaway said.