Terry Butcher has not had his tough-guy face on much after matches this season, but he wore it as he took questions following this third defeat in eight games.
This was the second cup competition Inverness Caledonian Thistle had departed from in that spell, and they lost two of their most important players to injury, which the manager admitted could have a big impact on their bid to hang on to second place in the Clydesdale Bank Premier League.
For Kilmarnock, however, this was a reminder of their run to Hampden and last year's Scottish Communities League Cup final triumph, and a victory that was completely deserved. Once the changes forced by three injuries in the first half had taken hold, the home team hurt Inverness more and more on the break.
As Butcher pointed out, though, the standard of replacements on either side influenced what happened after they were introduced.
"We lost Richie Foran and Andrew Shinnie, our captain and our most influential player. I looked at their bench and I saw experienced players: [Paul] Heffernan, [Garry] Hay, [Manuel] Pascali. We had young kids."
Thus, when Foran and Shinnie were replaced by Philip Roberts and Charlie Taylor, a loan signing from Leeds United, Kilmarnock could compensate for the loss of Cillian Sheridan by sending on Heffernan, their top scorer last season. He scored both goals: one a clinical one-on-one finish, one a wonderfully improvised flick to make something out of nothing.
"There's no getting away from his composure for the first one and his quick thinking for the second," said Jimmy Nicholl, the Kilmarnock assistant manager. "The manager [Kenny Shiels] had a decision to make in sticking with the young lads – Ross Barbour, Mark O'Hara and William Gros – and he got it right. They all did really well; Gros was excellent up front."
Foran had picked up a booking inside a minute, for a robust aerial challenge, and was replaced 15 minutes later. A scan will reveal the severity of his knee injury. Andrew Shinnie went for a one-two with Aaron Doran and pulled up short with a hamstring that tightened but, Butcher confirmed, did not tear. Shinnie was on his game, too, killing everything that fell to him, brave in possession, outwitting defenders.
A minute before the break, Kilmarnock lost Sheridan to a hamstring injury. He had been presented with two chances by James Dayton, but first could not outrun or outmuscle Josh Meekings to get the angle he needed to test Ryan Esson, then scuffed a terribly tame shot straight at the Inverness goalkeeper.
There was nothing more to it than that, other than the question of which coach would better react to a fast-changing picture on the pitch.
Heffernan was still cold when Borja Perez stood up a cross for him at the back post. The striker made it his but got his angle wrong and the ball went back across goal, never making it to the line.
However, if Shiels could have picked one of his forwards to run on to a freakish break of the ball, all alone in the penalty box, it would have been Heffernan. Taylor tackled Gros and the ball bounced off Meekings, who slipped as he tried to react. Heffernan took one touch and put a low shot across Esson and in.
Kilmarnock continued to break at Inverness, who by then looked a little less solid at both ends. Their goalkeeper kept them in the game as it entered its final stages. Esson dropped quickly to block a thunderous strike by Gros from 25 yards, then recovered to get in the way of the rebound, from Perez, eight yards out.
Cammy Bell needed to make one big save, from an Owain Tudur Jones header after the midfielder connected with Graeme Shinnie's corner. He got down to his left and held on well.
That set the table for more Kilmarnock counters and, after Hay had tested Esson with a brutal hit from distance, Heffernan wrapped things up with a poacher's goal. Ross Barbour drove the ball across the box and the forward moved his feet to redirect it past Esson from 12 yards.
"I was disappointed not to start, but I hope to stay in the team," said the striker afterwards. "The first one, I think their defenders got themselves in a bit of a mess and I had a lot of time to think about it, which is not always a good thing."
And the second?
"Right place, right time." But there is always more to it than that.
Men against boys