Jimmy Vesey scored the go-ahead goal early in the third period, helping the Rangers beat the Blues 4-2 on Friday night at Madison Square Garden.
Ryan Strome, Pavel Buchnevich and Chris Kreider also scored, and Alexandar made 44 saves for the Rangers, who had lost two in a row.
Vladimir Tarasenko and David Perron scored for St. Louis. Jordan Binnington stopped 20 shots in only his third regulation loss on the road this season.
Vesey found a loose puck during a scramble in front at 5:17 of the third to break the 2-2 tie. Brett Howden and Vinni Lettieri assisted on the play.