Those two goals turned a 1-1 contest into a 3-1 St. Louis advantage and the Blues went on to halt a two-game skid.
Andrew MacDonald produced the only New York goal 5:19 into the second to bring about a tie and it was all St. Louis after that with Jaroslav Halak making 27 saves for the win.
Magnus Paajarvi added a goal for the Blues late in the second period and Brenden Morrow scored in the third.
The Islanders' losing streak reached eight games. Anders Nilsson allowed all five goals on 26 shots.