He made 24 saves after allowing a goal to John Klingberg on the first shot he faced.
"I have so much confidence in this team and the way we play," Fleury said. "I think we're going to learn from our mistake here tonight, that we need more juice right from the start."
It was his first start since he made 28 saves on 31 shots in a 5-3 win against the Vancouver Canucks in Game 4 of the second round on Aug. 30.
"The decision to play Marc-Andre was because the same reason we started [Robin] Lehner in Game 7 (against the Canucks)," Vegas coach Peter DeBoer said. "I thought he gave us the best chance to win tonight. He was fresh. He's played well against Dallas. And he gave us a great game. I thought he was our best player. He gave us a chance to hang around when we didn't deserve to be in the game early. So you know, that decision was fairly easy."
Anton Khudobin made 25 saves for Dallas.
Fleury was 3-0-0 with a 2.67 GAA and an .893 save percentage in three games this postseason. He faced 23 shots in the first two periods, two in the third.
"That game is much more out of reach if not for [Fleury] the first two periods," Vegas defenseman Nate Schmidt said. "That's the truth. We didn't play well, and that game could have been a lot worse than 1-0 after two periods."
Lehner was 8-4-0 with a 1.99 goals-against average and .918 save percentage in 12 postseason games, including three shutouts against Vancouver. Lehner made 14 saves in a 3-0 shutout in Game 7 on Friday.
Since joining the Golden Knights in 2017, Fleury was 4-0-0 with a 1.25 GAA and .963 save percentage in four games against the Stars.
Prior to this postseason, Fleury started each of the Golden Knights' first 27 Stanley Cup Playoff games after they entered the NHL in 2017-18 and helped them reach the Stanley Cup Final in 2018, which they lost to the Washington Capitals.
Fleury won the Stanley Cup three times with the Pittsburgh Penguins (2009, 2016, 2017).
