Clarkson's goal at 11:28 of the opening period was his first of the preseason for New Jersey (2-3-0).
"I wish (the regular season) started tonight," Clarkson said. "I think we're all anxious and confident in here, ready to go."
Rick DiPietro stopped 20 shots for the Islanders (1-3-0). DiPietro missed the final 31 games of last season with a fractured orbital bone and a swollen knee following a fight with Pittsburgh goaltender Brent Johnson during New York's 3-0 loss on Feb. 2.
DiPietro was spectacular in turning away New Jersey's Vladimir Zharkov on a semi-breakaway in the second period and David Steckel's 2-on-1 attempt in the third.
New York rookie center Ryan Strome received a five minute major and a 10-minute misconduct for boarding Stephen Gionta with 3:14 remaining. The Islanders took 47 minutes worth a penalties.
"The guy kind of turned into me. I don't know how bad it was. I didn't mean to hit him too hard," Strome said. "I guess we'll see what happens."
The Islanders lost rookie right wing Nino Niederreiter to a groin injury in the first period. He will be re-evaluated Saturday.