Jordan Kyrou and Pavel Buchnevich each had a goal and an assist for the Blues (20-19-4), who had lost two straight and three of five. Joel Hofer made 21 saves for his sixth win in the past eight starts (6-1-1).
“We’ve got to continue to build off it,” St. Louis coach Jim Montgomery said. “We’ll enjoy this for a little while here and then we’ll get back to work tomorrow in anticipation for Saturday (against the Columbus Blue Jackets).”
Cam Fowler had an assist in his first game against his former team after St. Louis acquired the defenseman in a trade with Anaheim on Dec. 14.
Nikita Nesterenko and Sam Colangelo scored for the Ducks (17-19-5), who had won four of six (4-1-1). Lukas Dostal was pulled after allowing six goals on 22 shots. John Gibson stopped all 12 shots he faced in relief.
“We didn’t show up,” Anaheim coach Greg Cronin said. “We had no jump, we had no response. St. Louis played it like a playoff game, and we just were flat.”
The Blues scored three times in a span of 3:55 early in the first period.
Thomas gave St. Louis a 1-0 lead at 2:45, scoring off Jacob Trouba’s giveaway in the slot.
Tyler Tucker’s first goal of the season made it 2-0 at 4:31, a shot from the right point.
Kyrou then extended it to 3-0 at 6:40 on the Blues’ eighth shot, driving the net and finishing off Fowler’s flip shot.