Saad snapped a shot past Corey Price from the low edge of the right circle for the winner. Patrick Kane shot from the top of the slot and Canadiens defenceman Andrei Markov couldn't handle the puck.
Chicago's Jonathan Toews scored a power-play goal early in the third to tie it at 3. Michal Rozsival and Ben Smith connected at even strength as the Blackhawks won for the eighth time in nine games.
Montreal's Brendan Gallagher scored and set up 40-year-old Sergei Gonchar's first goal in nearly a year. P.K. Subban added a power-play goal for the Canadiens, who have lost two straight and are 1-4-1 in their last six.
Stay Connected
NHL.TV™
NHL GameCenter LIVE™ is now NHL.TV™.
Watch out-of-market games and replays with an all new redesigned media player, mobile and connected device apps.
Introducing the new official NHL App, available for iPhone, iPad and Android smartphones and tablets. A host of new features and improved functionality are available across all platforms, including a redesigned league-wide scoreboard, expanded news coverage, searchable video highlights, individual team experiences* and more. The new NHL App on your tablet also introduces new offerings such as 60fps video, Multitasking** and Picture-in-Picture.
*Available only for smartphones
** Available only for suported iPads