WATCH: All Jets vs. Blues highlights
The Jets (24-25-4) moved to within one point of the Blues (24-21-5) for the second wild card into the Stanley Cup Playoffs from the Western Conference. Winnipeg is 12-4-1 against Central Division opponents this season.
"We know they're big games," said Jets center Mark Scheifele, who had a goal and two assists. "We know they're important and we've got to buckle down for them and that's what we've done this year and we've got to continue to do it."
Blake Wheeler had a goal and two assists, and Patrik Laine, Nikolaj Ehlers and Jacob Trouba scored for the Jets, who opened a three-game road trip. Ondrej Pavelec made 24 saves.
"Overall it's a good win for us," Pavelec said. "It's a playoff race right now and every point is going to be huge, so I'm really happy with the win."
St. Louis has lost six of its past seven games at Scottrade Center (1-6-0). Alex Pietrangelo had a goal and two assists, and Vladimir Tarasenko had a goal and an assist.
"We made mistakes and we're paying for them right now," Blues coach Ken Hitchcock said. "We've got to minimize our mistakes. We've got to get more players playing to the same level that some of the guys played at today. There was some really good performances by some people today. We just have to get more people doing it."
The Blues scored first at home for the first time in the past nine games when Alexander Steen's shot caromed off the left skate of Jets defenseman Josh Morrissey in the slot at 3:37 of the first period for a 1-0 lead.
The Jets tied it 1-1 with 30.6 seconds left in the first on Scheifele's 23rd after an outlet pass during 4-on-4 play by Toby Enstrom.
Laine scored his 23rd goal 22 seconds into the second period to make it 2-1, and Ehlers scored at 5:53, seven seconds after a power play started, to make it 3-1.
Tarasenko scored with 52 seconds left in the second to make it 3-2. Trouba made it 4-2 after his pass caromed off Pietrangelo and past Allen at 3:33 of the third period.
Pietrangelo made it 4-3 with 12.2 seconds remaining with Allen pulled for a sixth skater, but Wheeler scored into an empty net with 2.3 remaining to make it 5-3.