BOSTON — Well, JR Smith had himself quite a night.The Cavaliers’ 107-94 loss to the Celtics in Game 2 of the Eastern Conference finals wasn’t kind to Smith. Or, you could say, he was up there in the pecking order of the culpable. When it was all over the Celtics were calling him “dirty.”It was Smith’s biggest TD Garden meltdown since Game 4 of the Cavs’ 2015 sweep, when Smith took a swing at Jae Crowder and cracked him in the jaw, earning a suspension.Let’s start with the basketball. On Tuesday, Smith was 0-for-7 shooting for no points. The player he often guarded, Jaylen Brown, led the Celtics with 23 points.There were myriad miscommunications on defense that led to wide-open Boston 3s. Smith was involved, though he was not alone in those missed assignments.”A few miscommunications,” coach Tyronn Lue said. “Of course he didn’t shoot the basketball well, but it was hard to get in a rhythm if you’re not getting consistent touches. Not too much worried about his shot. We know he can make shots, but just communication defensive-wise.”Smith explained: “We were slow on our coverages. Everybody had the right intentions, just communicating that a couple seconds late put us in tough positions and they capitalized on it.”Then there was the fourth quarter. Smith shoved Al Horford out of the air to make sure he couldn’t dunk and drew a flagrant-one foul, and was then given a technical for jawing with and shoving Marcus Smart after the play.”It was a good call. I blatantly pushed him,” Smith said. “It wasn’t like I was trying to lowbridge him or something to make sure he didn’t get it. It was a good, hard foul. I can understand why they gave me a flagrant.”Referees looked at the sequence — which occurred with 3:49 left in the game and the Celtics ahead 97-89 after Smith had missed a 3-pointer — the TD Garden serenaded Smith with a chant typically reserved for highway traffic disputes.