Jaskin finished with an NHL career-high eight shots on goal, one-quarter of the Blues' 32, and had four of St. Louis' 31 hits, two takeaways and two blocked shots playing 15:46.
Having already used forwards Zach Sanford and Ivan Barbashev in the playoffs, coach Mike Yeo decided to go with Jaskin (6-foot-2, 196 pounds) in a series that's become increasingly physical.
"Just the way the series has developed and get the feel for the way they're playing what to expect going into a game," Yeo said. "We felt he was a guy that ... I don't know that we thought he would be as good as he was tonight, because he was impressive. But we felt confident he would go in and play a really good game, but eight shots on goal, a big goal. I thought he was a force along the walls in both ends and a difference-maker."
Jaskin prepared himself with extra days skating by himself, or taking optional skates with few players, just like he did last season before he scored the tiebreaking goal in a 4-1 win against the Dallas Stars in Game 5 of an even second-round series.
"It's always hard when you have to bag skate and do extra stuff," the 24-year-old said. "It's about a mindset, and if you have this trait, it's good. There's a lot of days when it's difficult, but you have to push through it. That's what you have to do."