Canadiens 6, Panthers 2
Tom Pyatt, Plekanec and Ryan White scored 3:45 apart as Montreal beat Jacob Markstrom on the first, fifth and sixth shots they took on the Florida backup.
Mike Cammalleri had a goal and two assists, and Lars Eller added three assists for the Canadiens.
Plekanec and Jaroslav Spacek scored in the first, and Carey Price made 19 saves for his first preseason win.
Markstrom stopped 10 shots in the third. Tomas Vokoun made 19 saves in two periods.
Pyatt drove a slap shot past Markstrom 44 seconds into the third to increase Montreal's lead to 3-1. Plekanec scored his second at 3:47 to make it 4-1. White went to his backhand to score on the Canadiens' next shot at 4:29.
White and Florida's Mike Duco got major and game misconduct penalties amid a couple of fights at 12:47.
Erik Gudbranson, the No. 3 pick in this year's draft, needed stitches to close a cut on his left eyebrow after he was punched by Montreal's Travis Moen.
''I was pinned against the boards, and the refs were holding onto my arms so I was kind of hung out to dry there,'' said Gudbrandson, who also had a bulging welt below his left eye.
Panthers coach Peter DeBoer thought Moen took advantage of the 18-year-old defenseman's predicament.
''I don't know when it became all right in this league for a veteran guy to get a young kid hurt and in a vulnerable position and to keep throwing punches,'' DeBoer said. ''It was a play that I don't see how they can be proud of.''
Canadiens coach Jacques Martin said he ''didn't really see'' the incident.
''On our bench we don't have a good view how it started so I can't comment on that,'' Martin said.
Plekanec, who has four goals in three games, put Montreal up 2-1 with a short-handed goal late in the first.
Booth, who scored his third goal in two games, is bouncing back after playing only 25 games last season because of two concussions.
After tallying two goals in the Panthers' 3-2 win over Boston on Thursday in Rochester, N.Y, Booth put a rebound past Price to open the scoring 8:32 into the game.
Spacek got credit for the goal that drew the Canadiens even at 1 when his shot struck Panthers defenseman Dmitry Kulikov on its way past Vokoun at 15:57.
Booth earned his fourth point in two games with an assist when Weiss scored off a rebound 18:07 into the third to make it 5-2.
''He looks like he's back to the same old David Booth,'' DeBoer said. ''He's going into traffic, he's creating chances, he's using his speed, he's been physical - he looks like he's back and that's a good sign for us.''
Cammalleri scored with 33 seconds remaining.
Price, the Canadiens' uncontested No. 1 goalie after playoff hero Jaroslav Halak was traded to St. Louis, came up with his best result in three games. It didn't take much, though, to improve his outings in losses to Boston and Ottawa.
The 23-year-old Price entered with a 6.67 goals-against-average and a .750 save percentage after allowing 10 goals on 40 shots through his first 90 minutes of action.