Inverness progressed to the play-off semi-finals after defeating Ayr 4-2 on aggregate.
The Honest Men had taken a first-half lead through Luke McCowan to give themselves a fighting chance in the two-legged tie.
But Coll Donaldson’s first goal of the season was enough to rescue a 1-1 draw on the day and a clash with the defender’s old club, Dundee United, in the next round.
With a two-goal deficit from the first leg, Ayr had to come out swinging to get back into the contest.
They started brightly, with Declan McDaid and Lawrence Shankland forcing corners that eventually came to nothing.
Inverness started to settle into the game though, and they had a chance to go in front when Liam Polworth played a ball through to Jordan White.
It may have been slightly wider than the target man would have liked, but it was still a dangerous position that forced Ayr goalkeeper Ross Doohan to come out and smother the effort.
Caley Thistle won a corner, but it was Ayr who would take the lead a minute later.
The set-piece was cleared away, and McDaid took full advantage of having acres of space on the right flank to charge forward.
He had to pause as team-mates tried to catch up with him but the winger eventually picked out 19-year-old McCowan, who smashed the ball into the net in the 18th minute.
McDaid continued to be a thorn in Caley’s side and Robbie Crawford had a chance from the other side before half-time, cutting in from the left but missing the target.
White had a chance to equalise on the day for Caley Thistle with a volley, but it was straight at Doohan.
ICT seemed to tire in the second half, and they were lacking creativity even before Tom Walsh and Brad McKay were substituted with knocks.
So it looked like it was up to Ayr to find a way through, and Crawford curled an effort wide after good work from Michael Moffat.
Inverness would get an equaliser on the day in the end though, and it came from a set-piece.
With 11 minutes left on the clock, Aaron Doran was fouled in a good position and Polworth swung in a delivery that Donaldson got a glancing touch on to score.