Lawrence Shankland scored four times as Ladbrokes Championship leaders Ayr thrashed third-placed Dundee United 5-0 at Tannadice and went five points clear at the top.
Shankland put the visitors ahead in the second minute with a header past Benjamin Siegrist – who was substituted for Matej Rakovan soon after due to injury – and then doubled the lead with a close-range finish in the 41st minute.
Michael Moffat netted Ayr's third in the 78th, before Shankland completed his hat-trick with an 87th-minute penalty and notched his fourth two minutes later.
Having inflicted what was the Terrors' first loss under Robbie Neilson, Ayr are now six points better off than them and five ahead of Ross County, who are at Alloa on Saturday.