Two goals by Butch Goring and three points from Mike Bossy helped New York turn back visiting Edmonton in a meeting of last season's top two teams in the standings.
The Islanders, despite being without five regular defensemen, outplayed the Oilers for the final 40 minutes.
Goring, off to his fastest start in 14 years in the NHL, broke a 2-2 tie eight seconds into the second period. The veteran center scored his 10th goal this season when he stole a pass from Edmonton's Charlie Huddy, skated in on a breakaway and put a backhander past goalie Grant Fuhr.
Bossy made it 4-2 with his 17th goal, at 18:23 of that period, on another breakaway. Bossy beat Edmonton's Jari Kurri to a loose puck at the Islanders' blue line and skated free down the ice before beating Fuhr between the legs with a wrist shot.
Wayne Gretzky got an assist, giving him at least one point in each of Edmonton's 21 games this season. Gretzky leads the NHL in scoring with 46 points.
The Stanley Cup champion Islanders began the game without injured defensemen Denis Potvin, Tomas Jonsson, Mike McEwen and Stefan Persson. Midway thorugh the first period they lost defenseman Dave Langevin with a pulled muscle in his left leg.