That score also sent
The goal, Keane's 21st of the season, came after a perfect pass from midfielder Marcelo Sarvas freed him for a long run up the center of the field. He then pulled up deep in the 18-yard box, took aim and sent a right-footed shot past New England keeper Bobby Shuttleworth.
Keane then raced to the corner flag and celebrated with a cartwheel, which was quickly mimicked by teammate Alan Gordon.
Sunday's final was the ninth MLS title game to go to overtime and for the Revolution it was their fifth OT final in five trips. On three occasions those games were against the Galaxy, with New England losing all three.
The Galaxy last played into overtime in a final in the 2009 MLS Cup, losing to
Last year's championship also went to penalties before
Second-half goals by the Galaxy's Gyasi Zardes and New England's Chris Tierney forced the extra time.
Zardes, who had 16 goals in the regular season but none over the last two months, gave the Galaxy a 1-0 lead in the 52nd minute. But the lead lasted just 25 minutes.
The scoring play started wtih Stefan Ishizaki aiming a cross toward Zardes inside the penalty area. The ball took a deflection before Zardes settled it to the left edge, dribbled away from two defenders and drove it into the net at the far side.
The score came just seconds after New England felt it had been robbed at the other edge. Some sloppy ballhandling by the Galaxy allowed a Revolution rush into the 18-yard box but before he could shoot, New England midfielder Lee Nguyen was taken down in the box right in front of the goal.
Referee Mark Geiger immediately motioned for play to continue but some New England players argued for a penalty. And that gave the Galaxy, the best counterattacking team in the league, the opening it needed to push the ball quickly down the field and score.
Galaxy captain Robbie Keane had a chance to double the lead in the 70th minute, but after a pass from Marcelo Sarvas freed him for a brilliant run from inside the midfield stripe, Keane's weak right-footed shot from the center of the box made for an easy save for New England keeper Bobby Shuttleworth.
That nearly proved tragic for the Galaxy when the Revolution rushed downfield on a counter of their own before Kelyn Rowe pushed his right-footed shot wide of the far post.