The Panthers have three consecutive shutouts against the Canadiens, who have been held without a goal 12 games this season, most in the NHL.
Ekblad gave Florida a 1-0 lead with an unassisted goal at 18:31 of the first period. The Panthers defenseman jumped on a turnover in the slot and deked past defenseman Jeff Petry to shoot a backhand past Niemi for his 15th goal.
Barkov scored to make it 2-0 at 6:23 of the third period when his pass attempt from the left side deflected into the net off Montreal forward Logan Shaw's stick.
"There's a lot of confidence in this room," Ekblad said. "I'm not going to say wins come easy, because they never do, but a lot of us are feeling very confident in ourselves, you know, making strong plays and doing the right things."
De la Rose appeared to tie the game 17 seconds after Ekblad scored, but Panthers coach Bob Boughner challenged for offside, and the goal was reversed after video review showed Alex Galchenyuk entered the zone ahead of the puck at 18:43.