BOSTON — This year, the Washington Capitals appear to have saved their best for the postseason. Joel Ward slammed home a rebound at 2:57 of overtime to give Washington a 2-1 victory over Boston in Game 7 of their first-round playoff series Wednesday night, sending the Capitals to Eastern Conference semifinals and ending the defending Stanley Cup champion Bruins’ hopes of a repeat. Rookie Braden Holtby stopped 31 shots for Washington in the seventh one-goal game of the series. Matt Hendricks also scored for the Capitals, who barely made the playoffs this year after finishing atop the Eastern Conference in each of the previous two seasons — and winning just one postseason series combined. Tim Thomas made 26 saves for Boston, which was hoping to become the first team to repeat as Stanley Cup champion since the Detroit Red Wings in 1997-98. Tyler Seguin scored the Bruins’ only goal. 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. Note • Henrik Lundqvist of the New York Rangers, Jonathan Quick of the Los Angeles Kings and Pekka Rinne of the Nashville Predators are the finalists for the NHL’s Vezina Trophy for best goaltender. The winner will be announced June 20 at the league’s awards banquet in Las Vegas.