Like grammar school kids crossing days off a calendar while waiting for summer vacation, the Islanders are anticipating their fourth consecutive Stanley Cup by crossing off the Edmonton Oilers.

Tonight's 5-1 victory--won via a four-goal third period--gave the Islanders the luxury of a 3-0 edge in the best-of-seven series, and the knowledge that another 60 minutes of hockey here Tuesday night could finish off their season in the best possible style: with another championship.

"We were very sluggish in the first period, and for a long time, we looked like we had snowshoes on," said Islanders Coach Al Arbour. "I don't know if they're more used to these long trips, but we certainly looked tired till we found our legs in the third period."

Indeed, the first and second periods were mere exercises in frustration for both clubs. "I thought we played good hockey, even though we didn't get many chances," said Wayne Gretzky, who has been thoroughly stymied in this series with no goals and two assists. "But they (the Islanders) don't get rattled."

The Islanders had little reason to get rattled. With less than two minutes to go in the opening period, Mike Bossy made a save by scooping a loose puck away from the edge of his goaltender's net just before any Edmonton sticks could slip it behind Billy Smith.

"When Boss stopped one from going in our net, and we (went) up on the play, it was a big lift for us," Arbour said. Bossy took the puck into the Edmonton zone, shooting hard at Andy Moog. But his shot went off Moog's pad, and Anders Kallur had to move in and sweep the puck behind the goaltender with 19 seconds left in the period for a 1-0 lead.

Edmonton's goal came early in the second period, as Bob Bourne sat in the penalty box. Gretzky took the puck, whirling it to Jari Kurri, who shot it into the netting to tie the game as Smith went to his knees. The Islanders came back with four in the third period.

"I think when it was 1-1, we had some opportunities to go up," Gretzky said. "But then in the last period, they came back, as if the second period wasn't even there. That's where the experience helped them."

Whether it was experience or just plain determination after putting five shots on goal in the middle period, the Islanders took charge.

Bourne, enjoying his best playoff, scored the only other goal New York really needed after Stefan Persson slapped the puck from the blueline. Persson's shot was about to fall short of its target, but Bourne stepped in, going to the net and hitting the puck into the middle of the net as Moog sprawled helplessly outside his crease.

"It hit Moog, bounced in the air, and I just grabbed it with my stick, put it on the ice and sent it in the open net," Bourne said.

His goal signaled open season on Moog, as the Islanders displayed the kind of energy needed to win playoff games. "We just knew what we had to do," said Bossy. "And we just went out and did it."

A moment after Bourne's goal, defenseman Ken Morrow took a pass from Bryan Trottier and sent a 50-foot shot straight between the faceoff circles, and under Moog's right leg.

"I like to think we were due for some breaks at one point," said Edmonton Coach Glen Sather, looking very subdued. "But you can't take it away from them; they played an excellent third period."

If two early goals weren't enough to convince Sather, Duane and Brent Sutter emphasized the point further. Duane's goal came when Bourne came around Moog's net, spinning the puck out front toward his linemates, the Sutters. Brent's shot became a short rebound, but before Moog could jump to cover it, or anyone else in an Edmonton uniform could get close, Duane had flipped it behind the goalie at 16:43.

Then Denis Potvin took a pass from Duane, and shot it cleanly from the point, raising his stick in celebration as the puck beat Moog. Potvin had lined it in, but Brent Sutter tapped the puck as it flew by and was credited with the goal at 19:42.

Smith, whose 33 saves helped keep the Islanders on track to what could be their final game of the year, praised the defense for helping him. "When it was 4-1 in the third, I knew it would be tough to come back with that many on me," he said. "I've got 19 guys in front of me, playing their hearts out. But I was still scared for awhile." He shrugged. "That's the best way to play."