CLAUDE JULIEN could feel his Boston Bruins improving even though the results didn't show it. They did once the playoffs began.

Nathan Horton scored the go-ahead goal late in the first period, and the postseason-tested Bruins used a revived offense to beat the inexperienced Toronto Maple Leafs, 4-1, in their series opener last night.

"There were some signs probably the last four games or so [that] we seemed to be turning the corner," Coach Julien said. "We were playing better. We weren't getting rewarded with wins."

The Bruins had lost seven of their previous nine games, never scoring more than three goals. They played six games in the last 9 days of the regular season. Two games in the final week were postponed because of the Boston Marathon bombings and the search for suspects.

So after 2 days off and a new series starting, Julien believed his players' minds and bodies were refreshed.

"It's been draining for players to deal with that stuff," Julien said. "We're all sentimental to what happened to this city. It was just a matter of turning the page and getting a fresh start from the regular season.

"I think, mentally, that was a big difference. I think that's why you saw a big change in our team. We've been through this as a group."

The Bruins still have 17 players who were on the team that won the Stanley Cup in 2011. The Maple Leafs are in the playoffs for the first time since 2004 and have 15 players making their postseason debuts.

"It's a new experience for a lot of guys," Toronto forward James van Riemsdyk said. "That's a telltale sign how different the level is and how things can come back to bite you."

Game 2 is scheduled for Saturday night in Boston, where the Bruins have won six straight against the Maple Leafs.

The Bruins' late-season skid dropped them to the No. 4 seed in the East. That set up a first-round matchup with fifth-seeded Toronto, the first time the teams have met in the playoffs since 1974.

The Maple Leafs lost four of their last six regular-season games. Their shaky play continued after van Riemsdyk gave them a 1-0 lead in the first two minutes. They never scored again.

"We just self-destructed," Toronto coach Randy Carlyle said. "We didn't do a lot of things right. I've never seen so many people fall down with nobody around them with situations with our group. Like we said, we know this going to take more than an ordinary effort, and tonight it wasn't good enough effort."

In another game * 

At Pittsburgh, Pascal Dupuis scored twice, Marc-Andre Fleury made 26 saves, and the top-seeded Penguins opened the playoffs with a 5-0 romp over the New York Islanders.

Beau Bennett, Kris Letang and Tanner Glass also scored for the Penguins, who had no trouble even with star Sidney Crosby sidelined by a broken jaw. Doctors declined to clear Crosby, feeling his jaw wasn't healed enough for contact.

Fleury earned his sixth career playoff shutout. Game 2 is tomorrow in Pittsburgh.