Jake Neighbours also scored a power-play goal in the third for the Blues. Kevin Hayes scored in the second, and Pavel Buchnevich had three assists.
St. Louis also won on Saturday night, beating Minnesota 3-2 in a shootout.
“Tough back-to-back. Two games in under 24 hours,” Thomas said. “Those games are always tough, especially when they’re kind of waiting on you. We found a way to win and that’s the important thing. I don’t think it was our best game by any means, but when you find a way to win, you can’t complain.”
St. Louis (36-29-3) is four points back of Vegas for the second wild card in the Western Conference. The Golden Knights posted a 3-1 victory over the Devils earlier in the day.
Troy Terry scored two goals for Anaheim (23-42-3) in its sixth consecutive loss. The Ducks were shut out in their previous two games.
“We don’t shoot the puck enough,” Ducks coach Greg Cronin said. “We have the puck in the slot and won’t shoot it. It’s amazing to me.”
Anaheim finished a winless four-game trip to Chicago, Minnesota, Winnipeg and St. Louis.
Joel Hofer made 26 saves for the Blues. Rookie goalie Lukas Dostal had 23 stops for the Ducks.
St. Louis came up empty on three power plays in the first period. It was a much different story in the third.
“You can’t take six penalties,” Cronin said. “We killed three yeah but 50% isn’t a good percentage when you’re killing penalties. You don’t get measured by killing penalties in a period. It’s in a game, right?”
Thomas scored on a wrist shot from the slot at 1:53, giving the Blues a 2-1 lead. Neighbours helped with a screen in front of the net.
Neighbours used his stick to deflect in a shot by Brayden Schenn from the left circle, making it 3-1 at 6:12. It was Neighbours’ 22nd goal on the season.
“It’s tough for a goalie to react when pucks are changing direction right in front of them,” Neighbours said. “I’m trying to get better at it and work at it. I’m kind of lucky. I was trying to tip it down and it went up. I’ll take the lucky bounce.”
Thomas’ second goal of the period went off the stick of Anaheim’s Jackson LaCombe at 9:31. Thomas has 23 goals.
Terry scored at 19:52 after Dostal was pulled.
Hayes scored his 13th goal at 14:56 of the second, tying it at 1. Dostal failed to handle a Torey Krug shot and Hayes, at the side of the goal, knocked in the rebound.
Terry put in a rebound from just outside the crease at 13:41 of the first for the first goal in three games for the Ducks. They were held scoreless for 171 minutes, 50 seconds. It was Terry’s 18th goal on the season.
“This stretch is hard obviously. It’s hard on everyone,” Terry said. “It’s crucial not to start playing the wrong way, especially with the young guys and creating bad habits. We’ve got to keep playing the right way and not feeling sorry for ourselves.”
Up next
Ducks host Minnesota on Tuesday.