Montreal’s 1-0 victory played out before a crowd of 38,998 at CenturyLink Field.
The Sounders had the most chances, with forward Eddie Johnson seeming especially dangerous with several good chances – including one potential equalizer from close range that banged off the crossbar.
The lone goal came in the 35th minute, when Montreal’s Davy Arnaud got behind the Seattle defense at the penalty arc. Goalkeeper Michael Gspurning charged off his line, and Arnaud chipped the ball over the keeper and under the crossbar.
The Sounders were playing without several potential starters: Osvaldo Alonso and Marc Burch were unavailable because of disciplinary suspension; Adam Johansson and Patrick Ianni were out because of injury; and newly acquired Shalrie Joseph wasn’t fit for the 18-man roster.
Rookie DeAndre Yedlin, 19, made his professional debut, starting in place of Johansson.
The Sounders move next into the CONCACAF Champions League quarterfinal series, which starts Wednesday at Tigres of Mexico.
Their next MLS game is March 16, when the Portland Timbers visit.
Before the game, the Sounders parted ways with midfielder Christian Tiffert, apparently buying out his contract.
Tiffert was signed as a designated player on July 27, 2012. He played in 12 MLS games with 11 starts, recording three assists.