It was also DeSmith’s 13th shutout in the NHL.
Radek Faksa had three assists, Colin Blackwell had a goal and an assist, and Mikko Rantanen had two assists for Dallas (11-4-3), which improved to 6-1-2 on the road.
Jakub Dobes allowed five goals on 13 shots in the first two periods for Montreal (10-5-2), which lost consecutive games in regulation for the first time this season. Sam Montembeault made four saves on six shots in the third period.
Wyatt Johnston’s power-play goal at 14:21 of the first period gave the Stars a 1-0 lead. He was in the bumper position to one-time a feed from Roope Hintz.
Esa Lindell made it 2-0 at 3:50 of the second with a wrist shot stick side on Dobes from the left side of the slot on a pass from Faksa.
Tyler Seguin pushed the lead to 3-0 at 7:10 when he scored on a breakaway. Seguin drove in alone and put a snap shot past Dobes glove side after he got behind the defense to accept Robertson’s stretch pass from the Dallas defensive zone.
Robertson put the Stars up 4-0 at 15:10. He cut across the goalmouth to receive a pass from Thomas Harley and lifted a backhander over Dobes.
Robertson made it 5-0 just 1:39 later with a long-distance wrist shot through traffic for his second goal at 16:49.
Alexander Petrovic made it 6-0 at 2:01 of the third with a wrist shot past Montembeault. It was his first goal since April 2, 2018.
Colin Blackwell scored at 14:40 for the 7-0 final.