Allan Johnston has been involved in more derbies than Lester Piggott.

Rangers and Celtic, Hearts versus Hibs, the Tyne and Wear tussles and the stooshies of the Steel City. "I want to win this one more than the others," said the Kilmarnock manager in the build up to this all-Ayrshire affair in the second round of the Scottish League Cup. The 8800 paying punters packed into the stands clearly wanted it too as they generated a rip-roaring racket with kick-off looming.

This is a local coming together that dates back to 1910. The first time the two sides crossed swords, it ended 4-4. The last time they met, in the semi-finals of this same competition at Hampden in 2012, Kilmarnock winkled out a 1-0 victory in extra-time.

They did not need those additional minutes last night but for a spell it looked like they might. The Honest Men of Ayr put in a good honest shift and succeeded in frustrating their increasingly flustered hosts until the 69th minute. Rory McKenzie was the man who deflated Ayr and set Kilmarnock on their way in the competition they won two years ago.

Traipsing up to Rugby Park, there was an amplified preacher bawling his beliefs while holding a placard with the doom-laden predictions that 'tribulation, war and armageddon are coming'. The Ayr fans are not that rowdy, surely. The mob from down the A77 made their voices heard early on as the visitors made a sprightly start to proceedings. Nicky Devlin came leaping in at the back post to attack an inviting cross but he could not keep his header down and the ball sailed over.

The hosts slowly began to assert their authority, though. Jamie Hamill, with a good sight of goal, could only trundle a raking effort harmlessly wide after five minutes before Sammy Clingan came much closer two minutes later. From a free-kick right on the edge of the penalty box, he lifted a curler up and over the wall but it rattled off the crossbar.

Ayr survived another scare 20 minutes in. Tope Obadeyi pounced on Devlin's ditherings but as he raced in on goal he took one touch too many and Devlin managed to stick a blocking tackle in to salvage the situation.

Despite these moments of concern, Ayr were dealing comfortably with the menace and the first half would eventually meander to a fairly uneventful conclusion.

It was more of the same after the resumption with Kilmarnock toiling in their efforts to break down Ayr's spirited resistance. Josh Magennis knocked an effort wide, while Chris Johnston, a second-half substitute, swiped wildly at a good opportunity in the box after some neat and tidy build-up play.

After much huffing and puffing from the home side, the Ayr armour was finally pierced with just over 20 minutes left. Hamill's cross from the left picked out McKenzie lurking on the penalty spot and he thrashed the ball into the net. The relief was considerable.

Kilmarnock set about putting the tin lid on the triumph. Magennis had a header clutched by David Hutton before the Ayr goalkeeper beat away a powerful shot from Alexei Eremenko. Hutton then pulled off a fine flying save from a Clingan strike as Kilmarnock were thwarted in their efforts to make the last knockings that bit more comfortable.

As it turned out, things became decidedly uncomfortable for Johnston's team as Ayr mounted a late flurry. Peter Murphy had a close-range shot deflected over the bar before the hattered hosts emerged unscathed from a fraught melee in the box.