BOSTON – Coach 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 Wednesday night.

“There were some signs probably the last four games or so (that) we seemed to be turning the corner,” 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 nine 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 two 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 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 Eastern Conference.

That set up a first-round matchup with fifth-seeded Toronto, the first time the teams have met in the postseason 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. Like we said, we knew this is going to take more than an ordinary effort and tonight it wasn’t good enough effort.”

Wade Redden also scored in the first period for Boston, and David Krejci and Johnny Boychuk added goals in the second.

“That was a tough one to lose, especially with the start we had,” Nazem Kadri of Toronto said. “Undisciplined turnovers played a factor as well. We are just killing ourselves when we do those types of things.”

Toronto took a 1-0 lead on a power-play goal by van Riemsdyk just 1:54 in. Redden tied it at 16:20. Horton gave the Bruins a 2-1 edge 3:28 later.

Redden took a shot from the top of the right circle. Horton, sidelined the last five games with an upper body injury, lifted his stick and deflected the puck past goalie James Reimer.

After video review, it was determined that Horton’s stick stayed below the crossbar.

“To get that one was huge going into the second,” Redden said. “We didn’t really let off the gas, I don’t think, a whole lot. We kept going at them and got a few more big ones.”