CLEVELAND — On the bright side, the Knicks took the resurgent Cavaliers down to the wire.

On the dim side, it was another wildly erratic night for Julius Randle, outplayed by Cavaliers veteran Kevin Love and rookie Evan Mobley. And it was a missed late opportunity for RJ Barrett.

In failing a big test in Northeast Ohio against the fifth-place Cavaliers, the Knicks fell apart in the third quarter, rallied big in the fourth behind Barrett but dropped a 95-93 decision Monday at Rocket Mortgage Fieldhouse.

Barrett, after a slow start, came on in the fourth quarter, finished with 24 points, but shot long on a potential game-winning 3-pointer from up top with five seconds left.

Knicks coach Tom Thibodeau thought Barrett had a chance to drive the ball like he does best.

“I didn’t think we got what we wanted,” Thibodeau said of Barrett’s miss. “We wanted to attack in the open floor. He had been going downhill pretty good. I thought it would have been a good opportunity for him. We might have settled for that. Listen, it was a clean look. But I loved how he attacked the rim. In those situations, when you drive the ball, a lot of good things can happen.”

Barrett was more upset he missed five free throws than his choice to launch the 3.

“That was a great shot, good pass, good shot,’’ Barrett said. “I’ll take that shot 100 percent of the time.’’

When told Thibodeau felt he may have settled, Barrett said, “I haven’t seen the replay … but I thought I got a good look.’’

Meanwhile, Randle struggled on both ends while Obi Toppin, his backup, had one of his better performances in draining three 3-pointers.

Randle had one last chance to become a hero, taking an inbounds pass with 1.3 seconds left from Alec Burks, but fired a heavily contested airball from 40 feet. Randle was a minus-21, Toppin a plus-20.

On the final play, Thibodeau said the Cavaliers took the corner 3s away and gave the Knicks very little to work with.

“We had three options, it was a tough shot there,’’ Thibodeau said. “Credit to their defense.’’

Randle finished with 18 points and four turnovers, going 6 of 17 from the field, and walked off angrily. Love wound up with 20 points and keyed the Cavaliers’ game-turning 21-3 third-quarter run.

But it was Cleveland’s All-Star-in-the-making, point guard Darius Garland, who hit the biggest shot and the one that stuck in Thibodeau’s craw. Mobley collected an offensive rebound and the ball swung out to Garland, who hit a step-back 3 with 1:23 left to break the tie after faking out Barrett. Garland finished with 13 points and 12 assists.

“Basically it came down to a loose-ball offensive rebound they got and turned it into a 3,” Thibodeau said. “That’s the difference in the game.”

The actual difference is the Knicks have stopped hitting free throws recently. They were a dreadful 11 of 21. Barrett was 5 of 10 — the lone element to his game that hasn’t been stellar recently.

“Frustrating,’’ Barrett said. “That’s the game right there. That’s 10 points and we lose by two. It’s frustrating, especially for myself. You get there so many times, you got to be able to capitalize. You can’t play a team like that and miss that many free throws. It’s three of the last four games. Got to fix that.”

The Knicks were up 59-55 early in the third when the Cavaliers tore them up with a 21-3 run with Love punishing them and Randle failing on both ends.

The Cavs led 76-62 but after Randle came out, the bench went to town, particularly rookie shooting guard Quentin Grimes, who drilled two straight 3-pointers to cut it to 76-69 after three.

Thibodeau stuck with Grimes the whole fourth quarter and he finished with 12 points in 24 minutes and was a plus-21. He made 4 of 6 3s and played hard defense on Garland.

With Thibodeau sticking with Grimes in the rotation, newcomer Cam Reddish got his first DNP-CD as a Knick.

“For a young guy to come into the league — he’s not perfect — but he plays hard on every possession,” Thibodeau said of Grimes.

The Knicks played the Cavaliers even for the first half but ran out of steam on the second night of a back-to-back set to drop to 23-25 and see their one-game winning streak snapped.

“Sometimes teams are more rested than you are but it’s no excuse,” Thibodeau said. “You got to find a way to get it done.”