The veteran defenceman scored during a power play 4:22 into overtime to lift the Montreal Canadiens to a 4-3 victory over the New Jersey Devils on Sunday night.
It was Markov's fourth goal in as many games this season and was a third straight winner.
It came after the Canadiens wasted a two-goal lead in the third period as David Clarkson and Dainius Zubrus scored for New Jersey to force overtime.
"We played against a good hockey team that hadn't lost and that went to the Stanley Cup final last season, so it was a good measuring stick for us," said Montreal coach Michel Therrien. "We showed a lot of resilience."
Brendan Gallagher scored his first NHL goal and Brandon Prust got his first as a Canadien, while Ryan White also scored for Montreal (3-1-0).
Patrick Elias had the other goal for New Jersey (3-0-1). Elias and Clarkson had three points each.
While Markov was the overtime hero, the talk was all of young players Gallagher and his 18-year-old linemate Alex Galchenyuk, who had two assists.
Galchenyuk stole the puck from Andy Greene at the blue-line and sent a perfect pass across to Gallagher to fire into an open side past Martin Brodeur at 13:35 of the first period.
Gallagher didn't slide the length of the ice like Edmonton's Nail Yakupov, but the 20-year-old looked awfully happy as he leapt in the air and was hugged by his teammates.
"To get that first one is something you remember," said Gallagher. "Alex made a great pass. He looked off the D-man and put it right where it had to be. I just had to put it on the net."
They are both making a case to stay with the NHL club.
Gallagher, playing his third NHL game, made the team out of training camp after starting his first pro season with Hamilton of the American Hockey League.
Galchenyuk, the third overall pick in the June draft, has three points in four NHL games.
The team will have to decide after a game Tuesday night against the visiting Winnipeg Jets whether to keep Galchenyuk in Montreal or return him to the junior Sarnia Sting.
Therrien said only that the decision will be made with Galchenyuk's future in mind and won't be influenced by injuries or other factors. The team has lost left-winger Max Pacioretty for 3-to-4 weeks after he had his appendix removed on Saturday.
Therrien said "we like how (Galchenyuk) is developing on and off the ice.
"We're seeing a lot of combativity from the two young players. They were on the ice for two goals. They had a lot of energy. What's good is that they're learning and we're seeing results."
The youngsters are on aline with rugged veteran Prust, who has also been solid.
"We've got to keep doing the same thing — keeping it simple out there, moving pucks and hunting down pucks," said Prust, a former New York Ranger. "That's what made us successful."
The Canadiens, who had a 32-25 shot advantage, posted a rare win over Brodeur, who is 43-19-5 against Montreal in his lengthy career.
Montreal was first on the puck from the outset and scored 2:25 into the game when Alexei Emelin's shot was tipped by Travis Moen and went off Brodeur to White for his first of the season.
Emelin flipped the puck to the far blue-line where Greene lost it to Galchenyuk, who slipped a pass into the slot for the onrushing Gallagher to fire into an open side for a 2-0 lead.
The roles reversed in the second period as New Jersey camped out in Montreal's end and got a goal at 3:26 when Elias tipped a Mark Fayne point shot past Carey Price after some strong work in the corner by Clarkson.
Galchenyuk intercepted a clearing attempt and slipped the puck ahead to Prust to bat into the net two minutes into the third period.
Galchenyuk and Prust were both off for high-sticking when Clarkson banged in an Elias feed during a two-man advantage at 5:23.
Zubrus tied it at 13:02 on a feed from behind the net by Elias.
Markov was at the edge of the crease to lift the rebound of Rene Bourque's shot off the end boards in overtime. The Canadiens went on the man advantage after Greene took down Erik Cole going to the net at 4:01.
Notes: Montreal was without left winger Max Pacioretty, who was released from hospital Sunday after an appendectomy. He will be out 3-4 weeks. Lars Eller moved into his spot. . . Galchenyuk for Montreal and Stefan Matteau for New Jersey each played a fourth game. They can play one more before their teams must decide whether to send them back to junior. . . Defenceman Tomas Kaberle was a healthy scratch for Montreal.