Sergio's inconsistency at the finesse aspect was frustrating. After scoring 98 goals and 276 points in his final 132 junior games at the QMJHL level, Sergio never really strung together a great offensive season despite having all the tools. A strong straight-ahead skater, Sergio was good at handling the puck while on the fly. He also had great balance which made him hard to knock off of the puck. However he ran into trouble when he had to turn quickly. Like many big men, he turned much like an airplane on the runway. He had an extremely heavy shot, but seemed to take too long to get it off. He also developed into a two way player, at least to the point where he wasn't a defensive liability when he was on the ice.
Sergio's best year was in 1989-90 with St. Louis, his 5th year in the league. He scored 24 goals and 56 points and appeared to finally find his groove in the NHL, but too a step back the following year. He returned to the 20 goal level only one other time in the NHL.
While finesse inconsistency was frustrating, his physical inconsistency was maddening. Sometimes it seemed like he didn't want to play as big as he really was. If he had shown more consistency physically he would have really dominated. When he was hitting people he was really into the game, and his team usually did well that night. But too often it seemed like he was a sleeping giant out there, often unnoticeable. Sergio was huge at 6'3" and 215 lbs, and his good straightaway speed made for thunderous body checks. He was also immoveable in front of the net if he decided he was willing to pay the price that night. To his credit, when their was a big game or a playoff game, Sergio almost always brought his "A" physical game to the rink.
Sergio had a mean and down right nasty streak and the word around the league was not to anger him and he'd play the role of sleeping, and thus ineffective giant. If you awoke him he'd make you pay physically and his whole team seemed to respond favorably. Momesso would stick up for his teammates at any time, but often just placed a big bear hug on the guy as opposed to punishing that player. But if he did decide to punish you, my gosh look out! Just ask Dave "Charlie" Manson, one of the toughest though also physically inconsistent players of the day. Sergio landed a punch directly on a Manson's throat during a melee. Manson's voice was never the same as he was reduced to a raspy whisper from that day forward.
Drafted by his hometown Habs, Sergio was run out of Montreal as he floundered under intense media expectations. Despite one good year in St. Louis, it wasn't until he arrived in Vancouver that Sergio contributed solidly at the NHL level. Often playing as a bookend to fellow giant Trevor Linden with diminutive scoring star Cliffy Ronning in the middle, the line played really solidly for several years. The two giants on Ronning's wings enabled Cliff to emerge as a top center.
Sergio was traded to Toronto in 1995-96 in exchange for injured center Mike Ridley. However Sergio never found his niche in Toronto or in New York where he played with Rangers by season's end. Early in the 1996-97 season he was traded back to St. Louis where he finished the year quietly, scoring 1 goal in 31 games.
An unrestricted free agent after 1997, Sergio opted to leave the NHL and go over to Germany where he was one of the top players in Germany's top league which consisted of many former minor leaguers and fringe NHLers.