If J.R. Smith were in the lead to overtake Iman Shumpert for the Knicks’ starting shooting guard slot entering Wednesday’s preseason opener Shumpert sent a big message to skeptical coach Mike Woodson.

Woodson’s worried state about Shumpert’s knees and offensive repertoire went unfounded as Shumpert was driven to perfection.

Shumpert was 7-of-7 from the field to score a team-high 18 points as the Knicks hung on for a 103-102 preseason victory over the Celtics before 10404 fans at Dunkin’ Donuts Center.

Woodson revealed Wednesday Shumpert had knee soreness over the summer indicating his durability could be one reason Smith is potentially in line to go from sixth man to starting shooting guard.

Shumpert who scored 11 points in the second quarter made three 3-pointers against the Celtics and capped his night with a beautiful 1-on-1 15-foot pull-up jumper after dazzling off the dribble.

“He was great’’ Woodson said. “I don’t think he missed a shot tonight. He was poised. He has nothing to prove to me. In fairness to J.R. he is a big part of what we do and will be right in the mix when he comes back from injury. It’s going to be competitive.’’

At Wednesday morning’s shootaround Woodson said he believes moving Smith into the starting lineup could “expand his game.’’ Woodson sounded as if Smith is the favorite though Smith is still rehabbing from July’s patella tendon surgery and wasn’t in the house.

Woodson revealed part of Shumpert’s developmental program was shut down this summer because of his knees. Shumpert who came off ACL surgery last season said Wednesday his knees are now fine and the training staff felt it a natural reaction considering his surgical history.

Smith won the league’s Sixth Man of the Year Award last season and the role seemed suited for his game and personality. But he may be in store for a promotion — at Shumpert’s expense.

“I think he’s past that’’ Woodson said of Smith coming off the pine. “I want him to be past that. Let someone else get the Sixth Man [Award] — if he deserves to win the starting job. Last year was last year. He’s capable of defending [but] that’s the only question I have. I know Iman can defend and he’s still searching for the offense.

“You can go back and forth. I’m going to let the two fight it out.’’