Town boss Paul Lambert slammed his side’s display as they were beaten 2-1 by Coventry City, describing it as the “worst in [his] time" at the club.
The Blues were two goals behind at the break and never looked like getting back into the game until Luke Garbutt’s 86th minute goal triggered a late flurry which might have led to an underserved leveller.
"It wasn’t good enough, without a doubt that’s the worst in my time here,” he said. "In over a year that’s the worst performance we’ve turned in.
"Never deserved to go through, all credit Coventry, they were better than us, but that’s the worst performance in my time here.
"We were poor, we never turned up. We never got going, never did the basics of the game properly and you can’t mask the fact that we didn’t deserve to go through.
"All credit to Coventry, they were better than us right from the off. We were marginally better in the second half, marginally. But it wasn’t good enough that.”
He admitted that had Town grabbed a late equaliser it would have been a travesty: "I’m pretty sure if you asked [Coventry manager] Mark [Robins], if we’d have got an equaliser it wouldn’t have been deserved.
"I’ve been involved in games where the have been a lot of that, but we didn’t deserve anything, there’s no hiding it. A lot of fans had a really terrible night, it wasn’t good enough.”
What did he put the performance down to? "There are loads of things that can happen. I’ve been involved in games like that myself as a player. You try everything, it doesn’t come off and your touch doesn’t come off, everything you try doesn’t come off.
"It’s just one of those things when it happens. The game wasn’t the way we have been [playing]. The intensity wasn’t the way it has been. It just wasn’t good enough.”
Lambert made eight changes from the team which impressed in the first half as the sides drew 1-1 at St Andrew’s on Saturday. Might the changes of personnel have led to a lack of cohesion?
"It doesn’t matter what system you want to play, three at the back, five at the back, four at the back, two at the back, if you don’t do the basics of the game,” he insisted.
"It doesn’t matter, the principles are the same. If you don’t want to work and you don’t want to run and you don’t want do the basics of the game, it doesn’t matter what system you play.
"You can play like Pep [Guardiola]’s teams, you can play like Arrigo Sacchi’s team, whatever team you want to play, the basics of the game are that you have to be willing to work.
"It doesn’t matter what system you play, if you don’t want to make tackles, if you don’t want to make challenges, if you don’t to fight, it doesn’t matter.
"Systems, the principles of the game of football are that you have to work, you have to run and you have to be aggressive, they’re the principles of the game.
""Systems, you can ask any team, even go to Pep, Jürgen Klopp, the principles are the same. Nothing changes. On the basics of the game we let ourselves down, that’s what’s frustrated me.”
Can players lose the basics of the game through not having played regularly, as was the case with some of the team which started this evening?
"No, because we train at a high intensity,” Lambert added. "We train high, we train really hard, we have a good standard in training, training’s really good.
"Tonight it wasn’t there and, as I said before, it doesn’t matter what system you play, the basics of the game are that you have to work.
"And this football club, with the history that it’s got, before anything else, you have to earn the right, you have to work. The basics are working hard.”
He said he understood fans expressing their frustrations with boos marking the end of he first half and a second-half Alan Judge shot receiving a sarcastic ovation.
"It wasn’t good enough,” he reiterated. "There’s no masking that. I’m not going to come here and say ‘This was the problem we encountered here’ or make excuses, everybody that knows me or understands the game, has realism about the game, that wasn’t good enough.
"And it happens, those performances happen. The lads know it, they know it wasn’t good enough. I think everybody recognises that wasn’t good enough but one performance in over a year like that is, I’m not saying it’s OK, but I understand how it happens.”
Sky Blues boss Robins was delighted with his team's display before the break in which they established their two-goal lead.
"I thought we were brilliant in the first half,” he said. "I have been looking forward to getting a few of the players on the pitch for at the same time and I managed to do that today and from about 10 minutes in we settled down and got a foothold in the game, and I thought we played some really good stuff.
"Not only that, we looked assured and created good opportunities and chance to put them on the back foot and turn the crowd in a good first half performance.
"We got two brilliant goals, well-worked goals and we could have had more.
"Having said that, we could have been 1-0 down after 25 seconds from a big kick from their keeper but we knew as soon as we saw Tomas Holy in goal, that’s the way they play.
"They put you under pressure that way. We tired in the second half when there were some heavy legs.
"The rain didn’t help and the conditions were difficult tonight, especially in the second half, and everyone needs to take care driving home.”
Reflecting on the second half, he added: "I’m pleased with the way we played and dealt with things, although I’m a little disappointed that we didn’t capitalise on things in the second half because we had chances to go and take them and then we dropped a little deeper.
"And that’s why you concede late goals and why we were trying to get them up the pitch again.
"But I thought we defended really well and the two centre-halves were outstanding and headed everything they needed to head, apart from the one that they looped in and it got a flick, and we didn’t deal with it. Otherwise it was a really good win.”