A Clark Gilles wristshot 1:02 into overtime gave the New York Islanders a 2-1 victory over the Boston Bruins last night in the first game of their best four-of-seven NHL quarterfinal series.

The burly leftwinger took a cross-ice pass from linemate Butch Goring at the Boston blue line and broke past two defenders before closing in on Bruins' goaltender Gerry Cheevers and gently depositing the puck high to the far corner. Defenseman Gord Lane also picked up an assist on the play.

The goal, Gillies' second of the playoffs, stunned the Boston Garden crowd and ended a taut, tension-wracked contest that marked the first postseason meeting ever between the two clubs.

Islander goaltender Billy Smith and Cheevers starred in the nets as New York outshot Boston, 27-23. Despite numerous scoring opportunities for both teams, the game remained scoreless through the first two periods.

Boston's Peter McNab finally broke the deadlock 51 seconds into the third stanza. He lifted a rebound past Smith from a tangle of players in front of the New York net moments after the Islander goalie had kicked out a blast from the point by Brad Park.

The 1-0 lead proved short-lived, however, as the New Yorkers responded with a fluke goal at 3:49. Cheevers survived a close call when Bobby Nystrom's 65-foot slapshot grazed the right post, but had no such luck when Garry Howatt's blind centering pass from behind the net bounded off McNab's skates and into the cage.

Neither squad could find the twines again in regulation, as close-checking, careful hockey dominated the rest of the period.

The series continues tonight at Boston Garden before shifting to the Nassau Coliseum in Uniondale, N.Y., for two contests this weekend.

The Islanders, who were playing without injured forwards Mike Bossy and Anders Kallur, had defeated the Los Angeles Kings in four games to advance to the quarterfinal round. Boston had overcome the surprisingly tough Pittsburgh Penguins, three games to two.