DeBoer, who replaced Gerard Gallant behind the Golden Knights' bench in January, coached the San Jose Sharks throughout the two teams' bitter battle last season. Reaves recalled a tactic he used during one game to irritate DeBoer.
"Every shift that I went out there and there was a faceoff in the neutral zone near their bench, I would just stare at him and laugh," Reaves told TSN 1050's "OverDrive" on Thursday. "I could see it start driving him crazy."
Upon hearing that DeBoer had been hired in Vegas, Reaves admitted he was worried that his behavior could come back to haunt him.
"That's all I thought about when they said, 'Pete DeBoer is coming,'" Reaves said. "That whole game was just, like, flashing through my head. I was like, 'Oh man, I'm going to go down to the coast (East Coast Hockey League) after this.'"
Despite their history, DeBoer fit right into his new job with the Golden Knights, according to Reaves.
"It was seamless," Reaves said. "He's a great coach, he's a great guy, and it was a pretty easy transition."
The Golden Knights compiled a record of 15-5-2 after DeBoer took over and sit atop the Pacific Division with the season suspended.