Quentin Grimes' defensive skills on display against Donovan Mitchell

Sunday night’s game was supposed to be a showcase for Donovan Mitchell. It was supposed to provide a chance for the three-time All-Star to put on a show at Madison Square Garden and tease the Knicks with a reminder of what they failed on in the summer when they were unable to swing a deal with Utah to bring the native New Yorker home.

But perhaps it showed a hint of why the Knicks held up the negotiations on one name, refusing to add Quentin Grimes in a potential deal. With none of the high-scoring flash of Mitchell, Grimes helped the Knicks to a much-needed win over the Cavaliers by clamping down on the star that got away.

“I knew that was going to be a big matchup with everything that happened this summer,” Grimes said. “Come in focused. That’s one of the best players in the NBA. Had to stay locked in, and I feel like I did a good job on him today and we came out with a win.

“Yeah, definitely [the trade talk was on my mind]. I think people are lying if they say they’re not coming in with an edge and a chip on their shoulder. So just want to come in, just do what I do. Not worry about it too much because if I do that, I feel like I’ll get sidetracked. But come in with my mindset I have every day. I feel like I did that today.”

Mitchell scored 23 points but  shot 8-for-22 overall and 2-for-11 from three-point range. He had scored 38 points against the Knicks in an October game.

Grimes' statistics don't put on display why the Knicks have had faith in him. He played sparingly as a rookie and missed 10 of the first 15 games this season while battling a sore left foot, but he has started the last eight games and averaged 31.6 minutes per game, including 40:28 on Sunday.

Grimes has averaged 8.3 points in that span, still struggling to get into a rhythm shooting (just 25% from three-point range in the eight games), but he has solidified the Knicks' perimeter defense as well as provided a connection to the team's offense.

“He’s been playing his butt off every night,” RJ Barrett said. “It’s huge. We need him in that role. It’s good, especially what he did tonight against Donovan. That’s not something that’s easy to do.

"He’s a really good player. Definitely really happy to have him out there. Definitely try to help each other out there, but what he’s doing is special right now. Just trying to help him as much as we can."

It wasn’t just facing the player he could have been traded for in the summer. Grimes has taken on the toughest perimeter defensive assignment every game, ranging from Ja Morant to Devin Booker to Luka Doncic.

“I think that’s kind of happened in college,” Grimes said of taking on the toughest task every night. “That’s all [University of Houston coach Kelvin Sampson] stressed was defense . . .  I feel like he got me prepared every day to come with that mindset, really lock in no matter what defensively. You can have a bad shooting night, but you can always play defense and give effort on that end and affect the game that way.”

“I still think Quentin will get there offensively,”  coach Tom Thibodeau said. “He’s still finding his way. That’s gonna come. But his defense was terrific.

"The thing is, those guys are very difficult to guard individually, but Quentin has great feet. He has strength, anticipation and you’re going to have to work. And it’s not that he’s impossible to score against, because those guys, you can guard them great and their greatness is they’ve got the ability to make. But if you make them work, then over the course of the game — you make them work for those points, maybe that takes its toll over the course of the game.

"There’s a physicality to Quentin, too. On every play, he’s all out.”

By Steve Popper

steve.popper@newsday.com@StevePopper

Steve Popper covers the Knicks for Newsday. He has spent nearly three decades covering the Knicks and the NBA, along with just about every sports team in the New York metropolitan area.