NEW YORK — At their lowest point Tuesday night, the New York Knicks found the cure for their problems. He stood 6-5, weighed 220 pounds and wore a bushy black beard. And he played for the Cleveland Cavaliers.The Knicks set their eyes on James Harden and attacked him mercilessly. Down 22 points with 7:52 remaining in the fourth quarter, the Knicks spent the rest of regulation hanging their comeback hopes on Harden. They seized on the weakest spot in the Cavaliers’ defense and kept pressing.For 15 consecutive possessions, the Knicks went right at Harden. They switched him onto an island against Jalen Brunson. They sent him running around in recover mode. They forced him to twist and turn and shuffle and answer for every Brunson dribble and movement.It worked, maybe, beyond the Knicks’ wildest dreams. Those 15 possessions led to 30 points; they scored on 13 of them. By the time the Knicks’ reached overtime on Tuesday night, they had laid the foundation for not just beating the Cavaliers in Game 1 but for the rest of the series.“It was no secret we were attacking Harden,” Knicks head coach Mike Brown said after a 115-104 overtime win.Now, as the Cavaliers await Game 2 at Madison Square Garden on Thursday night, down 1-0 after blowing a golden chance to take an early hold of the Eastern Conference finals, they have to find a remedy for what ailed them down the stretch Tuesday and likely will for the next two weeks. The Cavaliers have a Harden problem. The Knicks made that clear. How will they solve it?The Cavs will need more from their All-Star guard. Harden had just 15 points in 42 minutes and missed 11 of his 16 shots. He did not create enough for others (just three assists) and again had more turnovers than made shots. His defensive shortcomings were laid bare at the worst times.After three quarters, it seemed that the Cavaliers could survive with a quiet night from Harden. They led by a big margin and hid him on defense. The double-digit lead was a reflection of a strategy well executed. But ultimately that had too-short a shelf life.In the fourth quarter, the Knicks sought Harden out when they had the ball, eventually wearing the Cavaliers’ defense down. Jalen Brunson scored 38 points, including 15 in the fourth quarter, and dished out six assists. Harden could not answer that onslaught with his own. There was no offensive rebuttal, no flurry he could catalyze to at least buoy the Cavaliers’ offense as it went silent in the midst of a collapse and the Knicks closed the game on a 44-11 run.“(Brunson) made some tough ones, but obviously we all know he’s a great one-on-one player and I think anybody on an island, it’s going to be difficult,” Harden said. “So we got to do a better job of making sure he sees bodies. On the other end, they do a good job of supporting him and helping him when he’s on an island. So he made some tough ones, but we got to do a better job as a team just because it’s not a one-man job. So, you got to be better in that aspect. I think he made a couple of them, which really got them going.”Harden’s teammates insisted he wasn’t the only problem. He wasn’t.“There’s different coverages and different ways,” Donovan Mitchell said. “Maybe we could have got to it a little bit earlier. Maybe get it out of Brunson’s hands. … This isn’t on him. This is on all of us. Just because of a certain stretch. Like, no. We still had opportunities on the other end as well to take advantage and score, and we didn’t. It’s not just on one person. He’s been around the league long enough — 17 years — he understands.”Cavaliers coach Kenny Atkinson said that he thought Harden “was good most of the game.” Maybe that was true, but the Knicks’ game plan indicated they didn’t think it would last. Atkinson said he never considered lifting Harden out of the game for the Cavaliers’ defensive possessions despite those troubles.“No,” he said. “He’s been one of our best defenders in these playoffs. I trust him. Smart. Great hands. I didn’t think about that.”After a Wednesday film review and walkthrough, Atkinson tried to shift the blame for the Cavs’ collapse off of Harden.“Everybody is putting it on James, but a lot of it is on our team, our team defense. We were great for three quarters, so we can do it. I’m sure some of it was him, there were a couple of blow-bys, but I’d argue it’s on the team defense, too,” he said.Brunson did attack Harden directly initially and got by him with ease. He invited screens to bring him into the action on eight straight possessions once the Knicks went down 22 and they scored eight straight times (though one was off a loose ball after Harden blocked Brunson’s shot). When the Cavaliers brought Sam Merrill into the game and threw him on Brunson, the Cavaliers kept two on the ball as the Knicks star kept seeking Harden out. That turned out nearly as bad for Cleveland as the Knicks put its defense into a blender and created open 3s.Atkinson will have to consider a broader suite of choices for Game 2. The Knicks are likely to keep attacking Harden. They found their easy button and kept pushing it.But they’ll need more from Harden on offense, too. He has long had a reputation as a playoff under-performer. His effective field goal percentage has dropped off dramatically in the postseason compared to his regular season work in Cleveland. His counting stats remain nearly even, but his efficiency has dipped. He has six games where he has more turnovers than made shots this postseason.When Mitchell slowed down in the fourth quarter and overtime on a night where he was the Cavaliers’ offensive engine with 29 points, Harden couldn’t pick up the slack. The Knicks, however, never relented.Harden has come through in needed moments this spring. He had 24 points and 11 assists in Game 4 in the last round against the Detroit Pistons and came back with 30 points on the road in Game 5. The Cavaliers will need that again and more frequently.Especially if the Knicks continue to try to make Harden the first line of defense. It worked Tuesday in the Eastern Conference finals opener. After 40 minutes, the Knicks finally landed on the countermove they needed. Now, the Cavaliers will have to figure out one of their own.