"I think it's completely revamped my entire hockey career," O'Reilly said on the "Hockey Sense Podcast" with Andy Strickland.
"In the NHL, never really getting a good taste of winning and never winning a playoff series and then coming here (St. Louis) and you win the ultimate hockey goal. It completely changed that part of me to be now known as a winner."
The 29-year-old pivot spent three seasons with the Buffalo Sabres prior to joining the Blues, and admitted to losing his love for the game in 2017-18 after Buffalo finished near the bottom of the standings for a third straight season. He was traded to the Blues that summer and has seen his career take off ever since.
O'Reilly potted a career-best 28 goals and 77 points in 2018-19, and earned the Selke Trophy for his dominant two-way play. In the playoffs, O'Reilly led the Blues with 23 points in 26 contests and claimed the Conn Smythe Trophy as postseason MVP.
After pacing the team in scoring with 61 points through 71 games this season, O'Reilly's success has left him hungry for more.
"It's been amazing but also getting a taste of it, you want to do it again and when you look at our team, we're going to have another opportunity to do that so there's a lot of excitement there."
St. Louis owned the top spot in the Central Division when the season was suspended in March, and will compete against the Vegas Golden Knights, Colorado Avalanche, and Dallas Stars in a round-robin tournament to establish the top four Western Conference seeds for the playoffs.