The home side were completely out of sorts for the first 74 minutes and it looked like the game could be heading for extra-time until Liam Miller jinked his way past two defenders on the right side before crossing low and when the cross was only half cleared by Derry, there was Gaynor to unleash an unstoppable volley from 30 yards which flew past Gerard Doherty in the Derry goal.
It was a goal worthy of winning any game.
The two goals that followed were harsh on Derry, who didn’t deserve to lose this one by three but Cork won’t be worried as they moved a step closer to a cup final date for the first time since they won the competition in 2007.
“We’re delighted to be in a semi-final. We had a lot of strong performances. Thankfully, we got the first goal,” City boss John Caulfield said.
“It was a hard game. We lost a night’s sleep so the turnaround was savage. Considering that, our second half was very good.”
Gaynor said: “Two minutes before I had a shot that hit the floodlight. I’m delighted though. It’s great to be in a semi.”
Caulfield made only one change to the side that drew 1-1 at the Brandywell on Friday night with John Dunleavy coming in for Alan Bennett.
Peter Hutton had to plan without striker Mark Quigley, who was out with a virus and he made four changes to his side with Ben McLaughlin, Stephen Dooley and Mark Timlin dropped to the bench. Their places went to Aaron McEneff, Philip Lowry, Cillian Morrison and Ryan Curran with Morrison playing in the lone striker’s role against his former club.
Derry were quick out of the blocks on Friday night and were 1-0 up within five minutes but the opening to this one was a much slower affair with the first real chance not arriving until the 14th minute when Mark O’Sullivan’s snap shot was straight at Derry ‘keeper Gerard Doherty.
The away side had a let off six minutes later when Doherty made a great stop to keep out Gaynor’s rasping effort and Dean Jarvis had to be alive to hack O’Sullivan’s header off the line from the rebound.
Derry began to come more into the game midway through a poor first half played in front of a very small crowd of 1,154, without threatening Mark McNulty in the Cork goal but it was the home side that looked the more likely to score. And it nearly arrived six minutes before the break when Michael McSweeney got in behind the Derry defence before scooping the ball narrowly over the bar from a tight angle.
Garry Buckley had a great chance to break the deadlock on the hour mark but he side-footed Billy Dennehy’s cross wide as the home side tried to up the pace.
With Cork out of sorts, Hutton made a double substitution in a bid to win the game when he introduced Mark Timlin and Stephen Dooley and the changes almost paid immediate dividends when Timlin picked the ball up 25 yards from goal and smacked a right footed effort off the butt of a post with McNulty making a great save to deny Morrison from the rebound.
Just as the home support were growing restless and Derry looked the more dangerous, the game was turned on its head in the space of four minutes when first Gaynor struck and four minutes later Billy Dennehy’s free-kick was headed home by Buckley.
Substitute John O’Flynn grabbed the third when he lobbed Doherty three minutes from time but the scoreline did flatter the home side, who will need to be a lot better if they are to book an Aviva final date with the winners of the Dundalk v Longford Town match when they meet Bray.
McNulty, McSweeney, D Dennehy, Murray (Bennett 75), Gaynor, Sheppard (O’Connor 86), Buckley, Dunleavy, Miller, B Dennehy, O’Sullivan (O’Flynn 75).
Doherty, Cornwall, McBride (McLaughlin 76), Barry, Jarvis, Curran (Timlin 61), McEneff (Dooley 61), Lowry, McNamee, McEleney, Morrison.
D Tomney (Dublin).