Denis Potvin's wrist shot 1:44 into the third period broke a 1-1 tie and started a three-goal rally with which the New York Islanders beat the New York Rangers, 4-1, last night to begin their Patrick Division final series in Nassau Coliseum.

Game 2 of this best-of-seven Stanley Cup quarterfinal also will be played in Uniondale, tonight.

Potvin got a loose puck in the slot in front of Ranger goaltender Ed Mio and shot it past Mio's glove to give the three-time defending champions a 2-1 lead. Bob Bourne set up the play when he controlled a carom off the boards, raced around the Rangers' net and tried to jam in the puck. His shot went wide, but Potvin scored on it.

Next, 2:43 later, Duane Sutter fought off a check by Ranger defenseman Ron Greschner and fed brother Brent Sutter in front for a short wrist shot that beat Mio. Brent returned the favor by helping Duane score on a power play at 8:05.

Bourne tied an NHL playoff record by assisting on all three goals in the final period.

"We were stronger in the third period," said Potvin.

These rivals, meeting for the fourth time in five years in Stanley Cup eliminations, played evenly through two periods. Greschner scored the only goal of the first period, shoveling in his own rebound on a power play at 13:01. It was the first power play goal yielded by the Islanders in the last 24 chances. Their penalty killing had stymied the Washington Capitals in the opening playoff round.

Islanders defenseman Stefan Persson made it 1-1 on a power play at 5:43 of the second period. Persson took a pass from Anders Kallur at the right point, took three strides toward the Rangers' net and slapped the puck past Mio's stick.

It was the Islanders' first power play goal in 16 tries.