BOSTON (AP) -- Joel Ward slammed home a rebound at 2:57 of overtime to give Washington a 2-1 victory over Boston on Wednesday night, sending the Capitals to the second round of the playoffs and ending the defending Stanley Cup champion Bruins' hopes of a repeat.
Rookie Braden Holtby stopped 31 shots for Washington in Game 7 -- the seventh one-goal game of the series. Matt Hendricks scored the Capitals' other goal.
Tyler Seguin scored, and Tim Thomas made 26 saves for Boston.
It was the first time in NHL history that a playoff series had seven games determined by one goal. Four of the games went to overtime, and two others were decided with less than two minutes left in regulation.
Hendricks scored midway through the first period, and Seguin tied it in the second. It stayed that way through a scoreless third, with Washington killing off a penalty in the final 3 minutes to send the game into overtime.
Patrice Bergeron had a chance to win it in the first minute of the extra period, but he couldn't get off a solid shot from Holtby's right. Two minutes later, the Capitals broke into the Boston zone with former Bruin Mike Knuble leading a 2-on-1.
Knuble shot, and Thomas left the rebound out where Ward could reach it with his backhander.
The building fell silent as the Capitals celebrated just their third postseason series win since a run to the Stanley Cup finals in 1998. Some fans littered the ice with debris, but the Bruins waited for the postgame handshake.
Thomas, bringing up the rear, gave Holtby a tap on the shoulder and said, "Great job, kid."
No team has repeated as Stanley Cup champions since the Detroit Red Wings in 1997-98.
Entering the postseason as a No. 7 seed, the Capitals won three times in Boston -- they also won Games 2 and 5 -- to earn a berth in the Eastern Conference semifinals. Their second-round opponent won't be determined until after Game 7s Thursday night between Ottawa and the New York Rangers, and Florida and New Jersey.
The Bruins tied it with 5:33 left in the second when Holtby kicked Andrew Ference's shot wide to his left to Johnny Boychuk, whose shot trickled through the goalie's pads and into the crease. Seguin dove for it, with two defenders crashing on top of him, and swiped it into the net to make it 1-1.