Since the Bruins acquired Taylor Hall and others at the trade deadline, the Bruins have won three straight games over the Islanders. The teams open their second-round playoff series on Saturday. Jeffrey T. Barnes/Associated Press

The season series between the Boston Bruins and New York Islanders was a tale of two seasons.

Early on, the Bruins were still incorporating some young players and were, at times, banged up as the Islanders won the first five games, four of which were at Nassau Coliseum. But the Bruins, with the influx of Taylor Hall, Mike Reilly and Curtis Lazar after the trade deadline, won the next three.

But beyond the infusion of talent, what exactly did the Bruins do better in the late-season wins than in the frustrating early losses? Now the Bruins will play the Islanders in the second round of the East Division playoffs with Game 1 is Saturday night at 8 p.m. at the Garden.

This series, of course, is a fresh start for both teams, said Boston Coach Bruce Cassidy, but improvements were made late in the regular season against the Isles.

“We had better third periods, for one,” said Cassidy. “I think that was a problem there earlier in the year, whether that was us not staying patient or not. … So obviously we managed the puck better in those last three games. I thought we were better on offense in terms of attacking their D, breaking them down and finding some ways to create some offense against their bigger D-men. That was below the goal line, some of it was off the rush. I know Taylor Hall definitely helped in that matter. We just played better at the end of the day and I think it showed on the scoreboard.”

Indeed, those third periods – a time at which the Bruins pride themselves on playing some of their best hockey – were not good early on against the Islanders. In the first meeting, Jean-Gabriel Pageau scored the only goal of the game with less than five minutes in regulation. They sealed the second game, a 4-2 win, with a power-play goal from Mathew Barzal and then a gutting shorthanded goal from Pageau. Then in one of their worst losses of the year, Islanders forward Anthony Beauvillier picked Trent Frederic’s pocket in front of the net, setting off a five-goal deluge in a 7-2 Boston loss. The Bruins played better in their last game at the Coliseum but still dropped it in a shootout.

Once the series shifted to Boston on March 25 the Bruins took a 2-0 lead, but that was Tuukka Rask’s return from his injury and he had to leave after a period before Boston lost in overtime.

Things turned after the trade deadline. The Bruins took the last three games at the Garden and Hall scored his first goal with his new team to seal the first win, using his speed for a partial breakaway for a third-period insurance goal. Cassidy hopes his speed can work as well even with defenders in front of him.

“Hopefully that’s what happens against this defense, where he does back people off to eventually where they respect his speed so much that they lose their gap and now all of a sudden some plays open up in front of their D and you get a little more ice to work with,” said Cassidy.

That the season series was mostly determined by home ice is not surprising. The Islanders were dominant in the Coliseum (21-4-3) and sub-.500 on the road (11-13-4), though they did get two wins in Pittsburgh in the first round. For the Bruins there was not a sizable gap, amassing 39 points at home and 34 on the road.

That’s a stark difference, but Cassidy sees much more in common with the Islanders.

“I think they have a lot of our attributes, right?” said Cassidy. “They want to play with structure, they want to play with discipline, they have good goaltending. Their D certainly want to get involved, but they want to play D first. They’ve got different lines that can hurt you. So in that regard we’re playing ourselves a little bit. Very well coached.

“So for us it’s a matter of staying within ourselves, playing the game in front of you. Put some pressure on their D, there’s no doubt. But I thought earlier in the year the games got away from us because of as much of what we did than what they did. The later games at home here, we managed pucks better and didn’t try to force the issue in games that were tight. We let game came to us, but at the same time dictate the terms.”

LAUZON DECISION SATURDAY: Jeremy Lauzon was due to participate in the Bruins’ optional workout Friday. Bruce Cassidy said no decision would be made on the defenseman’s availability for Game 1 until Saturday. “He’s going to go out today. We’ll make that decision tomorrow,” Cassidy said.

Lauzon, who hasn’t played since Game 1 of the Bruins’ first-round series with the Washington Capitals, returned to practice Wednesday in a non-contact jersey. He was a full participant Thursday and said he hoped to play.

“My goal is to be ready as soon as possible,” Lauzon said Thursday. “Every day I’m making good strides. In the end, it’s not going to be my call, but for sure I’m feeling better and better every day.”

KEVAN MILLER, who was injured in Game 4, hasn’t practiced yet and is further away. “He’s here. He’s on the bike. He’s not going to go on the ice,” Cassidy said. “That keeps him out of the lineup, but at least he’s progressing.”