Allen won his first career NHL start Wednesday in the Blues' 4-3 overtime victory over the Detroit Red Wings, snapping a five-game losing streak.
"It was a good feeling, especially getting off that slump we were on," Allen said. "Hopefully we can turn things around after the game. It was a big win. It was big for me. It was a good confidence boost."
According to coach Ken Hitchcock, Allen has given the club the opportunity to get both goalies into the form they found a year ago.
"It's allowed us to spend some time with Brian to hopefully get him back," Hitchcock said. "It's bought us some time with Halak. This was the first full-shot day for Halak and hopefully he can fully participate tomorrow to get ready for Sunday. Brian, this is two days in a row where Brian looks back on track."
St. Louis is expected to deploy the same lineup used in snapping its losing streak in Detroit.