The Islanders regained the lead on an Anthony Beauvillier tally midway through the middle period.
Buchnevich appeared to tie the game early in the third when he batted a flying puck out of the air on the side of the net that looked as if it went in, but was deemed no goal.
Pavelec allowed two goals on 15 shots through two periods before giving way to netminder Chris Nell for the third period. Pavelec said he's confident after two preseason appearances - both against the Islanders - before wrapping up his exhibition slate Tuesday night in Philadelphia.
"I'm feeling good every day," he said. "I'm feeling better every day. Training camp is a process. It's a lot of work. I'm happy for every minute I'm in the game that I can play. Starting to feel comfortable in the net and in the crease because practice and the game is two different things. It's been four periods now that I've played. It's better each minute."
Nell, who signed with the Rangers last spring out of Bowling Green, stopped everything he faced, including a breakaway opportunity midway through the period on Joshua Ho-Sang.
"I've seen a lot of highlight reels on him," Nell said. "I just kind of stayed patient and made him make the first move and hope it hits you."
J.T. Miller, Kevin Hayes and Brady Skjei were all alternate captains in the game. Despite it being just an exhibition contest, Skjei said it was still something he took pride in.
"It's a goal of mine in the future. I want to be a leader and a guy younger guys can look up to, talk to when they need someone to talk to," Skjei said. "It's just preseason, but whenever you get a letter on your chest, it's an honor."
The Rangers head to Newark to take on the Devils Saturday night at 7 pm.