Match ends, Ross County 2, Ayr United 0.
Liam Boyce and Michael Gardyne made the difference for Ross County with a goal in either half to take them safely through to the third round.
Jackson Irvine chested the ball into Boyce's path and the striker watched his shot deflect into the corner.
The visitors were unlucky in the first half, with Craig McCracken very close to an equaliser.
Just after half-time, Boyce fed Gardyne and the winger cut inside before netting a tremendous curling effort.
Both sides made five changes to their weekend line ups, with County demonstrating the strength and depth in their squad.
Most of the crowd expected a stroll after Jamie Reckord angled a ball to Irvine. He nudged into the path of Boyce, whose shot ricocheted into the corner for his third goal in two games.
However, the visitors looked determined and appeared the better side for long spells in the first half as County looked casual.
Ross Caldwell threatened to get behind the home defence on a couple of occasions but their best opportunity came from a free-kick.
Brian Gilmour curled the set piece into the area; it fell to McCracken but his firm shot sailed just wide.
Brian Graham perhaps should have buried a close-range strike but it eased just over the bar, before Marcus Fraser went close with a long-range effort that was parried away.
Any doubt about the result was ended when Boyce fed Gardyne on the right. He cut inside to a central area and bended a fabulous left-foot shot into the net.
Jim McIntyre's side looked far more purposeful after that.
Gardyne jinked on the right, and curled a left-foot cross to the back post that Boyce should have finished with a diving header.
Raffaele De Vita should also have netted when, with all the time in the world at the back post after good work from Gardyne, Graham and Fraser, he shot straight at Greg Fleming.
Graham then chipped over Fleming and, with the ball drifting just wide, De Vita looked certain to score but hesitated, presumably thinking he was offside, and the ball went past.
Micky Devlin might have pulled one back when played in by Michael Donald but seemed to panic as he lashed the ball over.
Graham and Tony Dingwall had further chances for County as they progressed comfortably against a more than competent Ayr United.
- 7GardyneSubstituted forHoldenat 78'minutes
- 24De VitaSubstituted forDingwallat 62'minutes
- 10BoyceSubstituted forQuinnat 82'minutes
- 8AdamsBooked at 51minsSubstituted forMooreat 58'minutes
- 10TroutenSubstituted forForrestat 23'minutes
- 9CaldwellSubstituted forPrestonat 45'minutes
- Craig Charleston
- Shots on Target
Second Half ends, Ross County 2, Ayr United 0.
Marcus Fraser (Ross County) wins a free kick on the left wing.
Foul by Michael Donald (Ayr United).
Attempt missed. Rocco Quinn (Ross County) header from the centre of the box misses to the right.
Attempt missed. Brian Graham (Ross County) right footed shot from outside the box misses to the left.
Foul by Scott Boyd (Ross County).
Jordan Preston (Ayr United) wins a free kick in the defensive half.
Attempt missed. Rocco Quinn (Ross County) right footed shot from outside the box is high and wide to the right.
Foul by Tony Dingwall (Ross County).
Craig Moore (Ayr United) wins a free kick in the attacking half.
Substitution, Ross County. Rocco Quinn replaces Liam Boyce.
Corner, Ross County. Conceded by Gerry McLauchlan.
Attempt blocked. Liam Boyce (Ross County) right footed shot from the right side of the box is blocked.
Attempt missed. Andrew Davies (Ross County) right footed shot from the centre of the box is too high following a corner.
Attempt blocked. Brian Graham (Ross County) right footed shot from the centre of the box is blocked.
Corner, Ross County. Conceded by Patrick Boyle.
Substitution, Ross County. Darren Holden replaces Michael Gardyne.
Attempt missed. Craig Moore (Ayr United) right footed shot from the centre of the box is high and wide to the right.
Attempt blocked. Brian Gilmour (Ayr United) right footed shot from outside the box is blocked.