Rock-bottom Airdrie suffered defeat against Raith for the fourth time this season as they lost 2-1.
In the sixth meeting between the sides this term it was the hosts who took the lead through Jamie Bain.
The defender netted his third of the season from close range after just seven minutes.
But on the stroke of half-time they were pegged back as Greig Spence turned the ball home from inside the six-yard box.
With 12 minutes remaining Grant Anderson drilled in Edward Malone's cross to give Rovers their first win in five matches.
United, meanwhile, have now failed to win in their last nine matches.