Meszaros and Scott Hartnell each scored a pair of goals, and goalie Brian Boucher was solid in relief of Sergei Bobrovsky (three goals allowed in 12 minutes, 5 seconds), enabling the Flyers to end a season-worst, five-game losing streak and a six-game skid at home.
Meszaros' second goal, a power-play tally, gave the Flyers a 6-4 lead with 10:20 left.
About 11/2 minutes before Meszaros' goal, Boucher preserved the Flyers' 5-4 lead with a glove save on Michael Grabner's breakaway attempt.
"Tonight was a little crazy, but we dug deep and got a win," Boucher said.
So now the Flyers head to the real season.
They know they have to play better than they did Saturday - their defensive coverage was extremely weak - if they hope to beat the Sabres.
"They have a lot of offense, a lot of skill guys, and quick guys," said Hartnell, whose bad-angle goal gave the Flyers the lead for good, at 5-4, late in the second period. "You have to close fast, and you have to stay out of the box. Playing with discipline is probably the biggest key in the first round."
"We've been waiting 82 games to get back to this point, and it's a big relief to get the second overall spot," said Hartnell, whose team lost to Chicago in last season's Stanley Cup Finals. "Now we can have some fun, win a few series, and get back to where we were last year."
Just like their play in the final two months, the Flyers were maddeningly inconsistent Saturday. They took a 2-0 lead in the first 47 seconds - 16 seconds shy of the franchise record, set in 2002 - on goals by Kimmo Timonen and Hartnell, then allowed the Islanders to tie the score at 3-3 with 7:55 left in the first period.
Timonen's goal, at 16 seconds, was the Flyers' fastest of the season. The two goals in 47 seconds were the Flyers' fastest at the beginning of a game since 2002.
"It was a good start, but a couple of turnovers by the blue line got us in trouble," said Danny Briere, who had a goal and two assists.
A Ville Leino turnover contributed to the Isles' first goal, a breakaway by rookie Grabner, whom Boucher called the NHL's fastest player. Before the first period ended, the Isles had tied the game at 3 and had the Flyers reeling.
Bobrovsky surrendered three goals on 10 shots. It was not the kind of confidence-building performance the Flyers were looking for from the rookie, who has been named the starter for the playoff opener.
Boucher, as he has done all season, will continue to mentor Bobrovsky during the week.
"He's bounced back, and he's been strong for us all year and had a great season," Boucher said. "He's got 28 wins as a rookie. I wish I had that as a rookie. He should be very proud. Now we'll get some rest and get ready for Thursday."
New York was 2 for 6 on the power play. In the last four games, three without injured penalty-killing leader Blair Betts, the Flyers surrendered six power-play goals in 16 chances.
Betts will be back in the lineup for Thursday's playoff opener. Chris Pronger, the team's defensive cornerstone, is also expected to return from a broken hand that has sidelined him for over a month.
Pronger "steadies things," defenseman Sean O'Donnell said. "We're leaning on our top four guys a lot now, and having him come back . . . and reducing some of Mez's and Kimmo's and some of those guys' minutes from 25 or 26 down to 21 or 22 is a big thing. We all know Chris has a presence."
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Flyers vs. Sabres
Game 1: Thursday at the
Wells Fargo Center.
Sabres entering playoffs on a hot streak. E10.