Chara's goal 8:12 into the third made it 6-3 and chased Kevin Poulin from the net in favor of Evgeni Nabokov, who came off the injured list earlier Monday following his second groin injury. The goal was the 500th NHL point for Chara, chosen by the Islanders in the third round of the 1996 draft.
"I am very fortunate to play in this league for so many years," Chara said. "Points have always been secondary in my view, but if I can contribute offensively it is a big plus."
Kyle Okposo, moved off the top line, had a goal and two assists for the Islanders, and Frans Nielsen and Michael Grabner also scored for New York, which lost its third straight (0-2-1) heading into its outdoor game at Yankee Stadium on Wednesday against the Rangers. Poulin made 30 saves.
"We played well but didn't bury enough changes," Okposo said. "We have to get over this loss and come back strong against the Rangers."
The Bruins recorded 18 of the first 20 shots.
Eriksson made it 1-0 at 7:47 when he scored his sixth goal and first in 12 games, dating to Nov. 25.
Momentum shifted with 7:50 left in the first when the Islanders received their first power play. They didn't convert, but found their game.
The Islanders got four of their 12 first-period shots during that power play and got even when Nielsen netted his 18th goal with 4:31 left.
New York started the second period on the power play after Chara took a penalty for throwing a retaliation punch at Cal Clutterbuck.
But again the Islanders fell behind. Marchand made it 2-1 at 4:50 when he took a pass in the left circle from Bergeron and lifted in a shot.
The Islanders answered again, taking advantage of a turnover in the Boston zone by Gregory Campbell. During a delayed penalty, Okposo made a pass into the middle to Grabner for his ninth goal and second in three games, scored at 8:20.
"That power play really gave them momentum, and we finished on our heels in the first," Bruins coach Claude Julien said. "From that point on until the end of the second period, I thought we got really sloppy and shot ourselves in the foot."
The Bruins went ahead 3-2 at 12:21 during another delayed penalty. Shawn Thornton's pass hit New York's Matt Martin and caromed to Smith, who tapped in his 17th goal.
Another Bruins breakdown cost Boston the lead again. Defenseman Dougie Hamilton leaped at the blue line to knock down a puck, but missed. The speedy Grabner took off and was joined by Okposo, who came out of the penalty box.
They came in on a 2-on-0 break and passed the puck back and forth before Okposo slammed in his 23rd goal with 4:52 left.
It appeared the teams would be tied to start the third, but Soderberg steamed in on the right wing, got around defenseman Thomas Hickey and beat Poulin with 32.7 seconds remaining.
The Bruins posted their first two-goal lead when Bergeron slammed in a feed from Marchand at 2:17 of the third.
"We can't panic," said Islanders captain John Tavares, who had a six-game point streak snapped. "Have to trust each other in this room."
Okposo has seven goals and eight assists since his daughter was born earlier this month. ... The Islanders activated D Lubomir Visnovsky off the injured list. ... Rask is expected to start Tuesday when the Bruins host Florida.
Copyright by STATS LLC and The Associated Press
UNIONDALE, NY - JANUARY 27: Chad Johnson #30 of the Boston Bruins protects the net against the New York Islanders...