The Bruins grabbed a 3-0 lead around the midway point of the second period in Monday's game in New York, but the desperate Rangers scored five unanswered goals to take a 5-3 decision at Madison Square Garden.
Having clinched a playoff spot and the division title, Boston has little left to play for in the regular season. Although, the third-seeded Bruins are now just four points behind slumping Philadelphia for the East's second spot and Boston will get to use a game in hand over the idle Flyers tonight.
After this evening's tilt, the Bruins will host Ottawa on Saturday before closing the regular season Sunday in New Jersey.
The Islanders, meanwhile, have been eliminated from playoff contention and have lost four of their last five games. New York has missed the postseason four straight years since its last appearance in 2007.
After grabbing the three-goal lead on Monday, Boston allowed New York to cut the score to 3-2 at the end of 40 minutes and the Rangers eventually took a 4-3 lead on Michael Sauer's tally with 2:57 remaining in the third period.
Daniel Paille, Nathan Horton and Chris Kelly each tallied for Boston, while Tim Thomas made 21 saves in defeat.
The Bruins have won four of their last six at home and are 20-13-6 as the host this season.
The Islanders last played on Saturday, when they were dealt a 4-2 loss by the visiting Carolina Hurricanes. New York also blew a lead in that setback, as the Isles were ahead 2-1 after 40 minutes before allowing Carolina to score the final three goals of the game.
Jesse Joensuu and John Tavares lit the lamp for the Islanders, while Al Montoya turned aside 22-of-25 shots.
New York is playing two of its last three games of 2010-11 on the road, as tonight's tilt and Saturday's season-closing game in Philadelphia are sandwiched around Friday's home test against Pittsburgh. The Islanders are 17-18-5 on home ice compared to a 13-19-7 mark away from Long Island.
Boston has taken two of three from the Isles this season, although New York recorded a 4-2 home win when the clubs met last on March 11. The Bruins have still taken 10 out of 13 in the series overall and the Isles have lost seven of their last eight in Beantown.