Ayr ended a six-game winless run and sent Alloa to the foot of the Scottish Championship with a 4-1 victory.
United were without a win since beating the same opposition away from home on December 5 and once again proved too strong for Athletic.
Tommy Walsh's sixth-minute strike was cancelled out within five minutes by Alan Trouten's free-kick, but once Ayr retook the lead, Alloa had no response.
After Luke McCowan bent in a second on the half-hour mark, Aaron Muirhead made it three from the penalty spot after Michael Miller was fouled, and McGowan's second made it four with 20 minutes still to play.
The result lifts Ayr up to fifth in the table, but Alloa sink to the bottom after Arbroath's win at Morton.
