Halák was named as the Canadiens' Molson Cup Player of the Year for the 2009–10 season and he was also named as the starter heading into the first-round playoff match-up against the President's Trophy-winning Washington Capitals. In the sixth game of the series, He stopped 53 shots to set a team record for a playoff game (in regulation-time) and lead the Canadiens to a 4–1 victory. Ultimately, the Canadiens overcame a 3–1 series deficit to win the series in seven games, marking one of the biggest upsets in NHL history.