"It's one win," Dupuis said. "We definitely feel good about it but we've just got to put this one behind us and get ready to work for the next one. They'll definitely look at tape and come out harder, that's for sure."
The Islanders will have to if they have any hope of making the series competitive. Making its first playoff appearance since 2007, New York fell behind less than 5 minutes in and never recovered.
"I thought some guys worked hard and played a good game," Islanders coach Jack Capuano said. "Again, with our club we need all 20 guys going, and we didn't have all 20."
That isn't an issue for the staggeringly deep Penguins.
Rookie Beau Bennett, enforcer Tanner Glass and defenseman Kris Letang also scored for Pittsburgh, which had no trouble against the upstart Islanders even with Crosby relegated to cheerleader.
Fleury earned his sixth career playoff shutout while playing behind a defense that appears to have learned a few lessons from last spring's embarrassing opening-round loss to Philadelphia.
The Flyers shredded Pittsburgh for 30 goals in six chaotic games. The Penguins have emphasized being responsible on defense all season, knowing their wealth of offensive talent will come to life when needed.
Bruins 4, Maple Leafs 1 • In Boston, Nathan Horton scored the go-ahead goal late in the first period, and Boston used a revived offense to beat Toronto in the playoff series opener.
The Bruins scored more than three goals for the first time in 10 games. They closed the regular season on a 2-7 skid that dropped them to the No. 4 seed in the Eastern Conference.
Boston 4, Toronto 1
Pittsburgh 5, N.Y. Islanders 0
San Jose 3, Vancouver 1
• Ottawa at Montreal, 5 p.m., CNBC
• NY Rangers at Washington, 5:30 p.m., NBCSN
• Los Angeles at St. Louis, 7:30 p.m., CNBC
• Detroit at Anaheim, 8 p.m., NBCSN