Sittler, the leading scorer in the franchise's storied history, was honored during an emotional pregame ceremony as his number joined those worn by Turk Broda, Johnny Bower, Bill Barilko, Ace Bailey, King Clancy, Tim Horton, Charlie Conacher, Ted Kennedy, Syl Apps and George Armstrong above the rink at the ACC.
Five captains removed from Sittler, Sundin opened the scoring with a power-play goal late in the first period and made it 2-0 early in the second.
Defenseman Jyrki Lumme also scored and Alexander Mogilny and Nik Antropov each picked up two assists for Toronto, which had not won five in a row since Dec. 6-15, 2001. Ed Belfour was headed toward his league-leading seventh shutout, but a giveaway by Mogilny led to Jan Bulis' goal with 3:45 to go in the third period.
That was the lone bright spot for Montreal, which has lost four straight to fall to 3-4-2-1 under new coach Claude Julien.