The Coyotes vaulted past Los Angeles into first place by a point in the Pacific Division. The regular-season ends Saturday, with Phoenix meeting Minnesota and Los Angeles taking on San Jose.
St. Louis lost its fourth in a row and missed a chance to move into a tie with Vancouver for the most points in the Western Conference. The Blues have the tiebreak advantage over Vancouver but they need to win Saturday while Vancouver loses for that to make any difference.
It was the Coyotes' fourth straight win.
Brian Elliott allowed the four Phoenix goals on 32 shots.
Every NHL team will be in action Saturday on the final day of the campaign. All 16 playoff berths have been filled, but seedings and playoff matchups are still to be determined in both conferences.