The Lightning made it three wins in three nights thanks to their biggest free-agent signing this summer, Valtteri Filppula, who assisted on three of their four goals at Scottrade Center.
Artem Sergeev, Brett Connolly, Ondrej Palat and Pierre-Cedric Labrie scored for the Lightning. Ben Bishop, who grew up in St. Louis, and Anders Lindback split time in goal for Tampa Bay. Bishop stopped 14 of 15 shots; Lindback made 13 saves on 15 shots.
"That was a big strong team who had a lot of NHL regulars in the lineup and our guys found a way, so we were proud of them," coach Jon Cooper said.
"He's got to play. He's got to compete. He's got to get back into the rhythm," Blues coach Ken Hitchcock said of Halak, who missed much of last season with injuries. "He's going to have to work at it."