Mark Docherty's double helped Alloa ease past Ayr into the fourth round of the Scottish Cup with a 4-0 win in the replay. It was 1-1 in the original third-round match, with Alloa's Liam Buchanan and Ayr's Ryan Donnelly netting, and Buchanan struck first in this tie after 24 minutes.After an even start to the match, the home side's forward found space in the box and slotted past David Hutton for his eighth goal in 18 appearances.Daryll Meggatt doubled their lead four minutes later when he headed home Docherty's free-kick. Docherty was soon on the scoresheet himself, after latching onto the end of Michael Doyle's ball to coolly finish and make it three for the Wasps. Docherty's second of the evening came on the hour-mark as he came inside and curled an effort into the far corner, doubling his tally for the campaign and confirming the win for Barry Smith's men.