NBA

How flaky J.R. Smith became LeBron’s perfect running mate

Once upon a time, J.R. Smith, a Freehold, N.J. native, considered playing with Carmelo Anthony and the Knicks the pinnacle of his career.

But nobody sounded more grateful to be in Cleveland and out of the Knicks’ sinkhole than Smith late Tuesday night while wearing a black “F’’  cap on the postgame podium, sitting next to NBA icon LeBron James. The “F’’ stands for Finals.

As he fiddled with his headwear, the always flaky Smith said, “I’ve never worn one of these.’’

Smith and Iman Shumpert are into the NBA Finals just four-and-a-half months after being part of Phil Jackson��s train wreck. Smith notched his second straight double-double Tuesday to aid the Cavaliers’ 4-0 sweep of the Hawks with 18 points and 10 rebounds to move into the NBA Finals starting June 4 vs. either Golden State or Houston.

Smith clutched his young baby niece on the stage erected on the court for the Eastern Conference championship ceremony.

Smith embraces Cavaliers coach David Blatt.Getty Images

“It’s unreal. I came out of the game, and I gave Coach (Dave Blatt) a hug, gave Bron a hug, and all these guys,’’ Smith said. “When I looked at Shump, and I just looked in his eyes and see where we came, where we started from. My mom was on the court when all the confetti and stuff was coming down. She’s like, talk about starting from the bottom, and now we are here.’’

Smith and Shumpert were shipped by Jackson in a fire sale trade on Jan. 5 one hour before the Knicks tipped off in Memphis. The Knicks’ record was 5-31 after dropping 21 of 22 games.

“To be able to do this, it’s unreal to be in this situation and this position,’’ Smith said. “I could have been in the worst situation, but my prayers have been answered. I’m playing with arguably the greatest player to ever play the game. People that come in every day and enjoy what they do and work hard at what they do, like Tristan (Thompson) and the rest of the guys. I’m in a great situation, and I just want to take full advantage of everything I can at this point.’’

The quirky Smith relished the moment. At one juncture on the interview podium, he took a selfie photo of himself with James and Thompson to post on his Instagram account.

“That’s J.R. for you,’’ James said to laughter.

Smith chimed in: “That’s @teamswish on Instagram, if you ever want to follow. Trying to get 2 million or so. Trying to catch up with LeBron.’’

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Smith aided that cause by later posting a celebratory lockerroom rap featuring himself, James, Shumpert and Kendrick Perkins.

King James has become fast friends with both Smith and Shumpert and seems to be enjoying himself on the court more than in his years in Miami with buddies Dwyane Wade and Chris Bosh. The Cavaliers made the big decision in January to move Dion Waiters to the Thunder and add Shumpert  and Smith in one trade and acquiring ex-Knicks center Timofey Mozgov, a 2011 casualty of the Anthony trade, days later.

Late Tuesday night, James reflected on the moves, noting the club was 19-20 before Smith and Shumpert came to Cleveland.

“It put our team to a place where I thought we could compete,’’ James said. “I knew if we had the pieces we would compete.’’

After knocking off Chicago, Smith posted an Instagram a split photo of himself and Shumpert in Knicks and Cavaliers’ jerseys with the heading: “One Man’s Trash. Another Man’s Treasure.’’

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Smith rebounded from a low moment at the end of the first-round series vs. Boston when he got suspended for the first two games of the second round vs. the Bulls for smacking Jae Crowder. Shumpert was then elevated to the starting lineup as Blatt decided to keep Smith as the Sixth Man.

Since taking on that role, in eight games, Smith has averaged 15.4 points on .500 shooting from the field, .459 shooting from 3-point land, in 31.4 minutes. In Game 4, Smith hit an impossible stepback 3-pointer in the first half as the Cavs pulled away. He set up Thompson for a brilliant alley-oop pass and showed his connection with James by cutting without the ball down the lane where James made the perfect feed for a layup.

Shumpert has excelled as a starter on both ends, as well, being one of the offensive keys in downing Chicago. In the clincher Tuesday, he scored just three points, but had eight rebounds and four assists.

It seems like another season when Smith, Shumpert and Anthony marched into Quicken Loans Arena in late October and handed James and the Cavaliers a stunning defeat in their ballyhooed season opener that heralded The King’s return to Cleveland.

James said Tuesday: “I couldn’t foresee us in The Finals at the beginning of the season.’’