LAS VEGAS — As the Vegas Golden Knights swarmed Marc-Andre Fleury inside his crease at Bell MTS Place in Winnipeg, one of his most fervent supporters hoisted a sign amid a raucous fete back in Las Vegas.

Standing mere feet from a stage at the team’s official watch party, Paul James, a former air traffic control specialist at McCarran Airport, celebrated with a bevy of cheerleaders, thousands of fans and the team’s eponymous Golden Knight mascot, who waved a shiny rapier in triumph. The sign read: “Pouvoir Des Fleury” or “Flower Power,” underlining the acrobatic goaltender’s magnetic appeal to the team and city.

On Sunday, Fleury led the Knights to a 2-1 victory over the Winnipeg Jets, capping an improbable and amazing journey through the Western Conference playoffs. Over the series’ five games, Fleury constantly repelled a talented Jets lineup that included the imposing forward Mark Scheifele and the sharpshooter Patrik Laine.

With the victory, the Golden Knights joined the 1967-68 St. Louis Blues as the only expansion teams since 1960 in the N.H.L., N.B.A., M.L.B. and N.F.L. to earn a spot in a championship round during their inaugural seasons.