"It was a tough week for them, and I thought they responded the right way," DeBoer said. "They came out, they poured their energy into the game, playing the right way, and we got rewarded for it. Hopefully it's the start of a roll here."
DeBoer was hired on Wednesday, replacing the fired Gerard Gallant. DeBoer was fired by the San Jose Sharks on Dec. 11.
"I thought our leaders led tonight," DeBoer said. "I thought Mark Stone] was the best player on the ice, and everyone else kind of jumped on board."
***[WATCH: [All Golden Knights vs. Senators highlights]*
Stone had a goal and an assist in his return to Ottawa; Vegas acquired the forward in a trade with the Senators on Feb. 25, 2019.
"It was weird, for sure," Stone said of playing his first game for the away team in Ottawa. "Six great years over there. They took a chance on me from Day 1. I was no shoo-in to be an NHL hockey player and [the Senators] kind of helped me develop and molded me into the player that I am today. It was unfortunate that we ended my career here, but at the same time, Vegas has become home and it's now the place that I want to spend the rest of my career."
Golden Knights goalie Marc-Andre Fleury tied Henrik Lundqvist for fifth place in NHL history with his 458th win. He made 33 saves and ended a personal three-game losing streak.
"I felt better tonight," Fleury said. "I think I made more key saves to keep us ahead in the game."
Connor Brown had a goal and an assist, Vladislav Namestnikov scored, and Craig Anderson made 39 saves for the Senators (16-23-8), who have not won in nine games (0-5-4), their longest stretch of the season without a victory.
"Obviously, [Vegas] was motivated with all the changes going on and [Stone] coming back to play here," Brown said. "It was a good effort to push back, but obviously not good enough out of the gate."
Paul Stastny had a goal and an assist for Vegas (25-19-6), which ended a four-game losing streak.