After a mediocre first season in St. Louis during which he recorded 26 points in 53 games, Momesso's career took an upward turn in 1989–90 when he was placed on a line with superstar sniper Brett Hull and playmaking centre Adam Oates. Spending much of the season on the Blues' top line, Momesso turned in the most productive year of his career, finishing with 24 goals and 32 assists for 56 points, along with 199 penalty minutes. However, he would lose his spot on the top line in 1990–91, and recorded just 10 goals through his first 59 appearances.