The City Under-18s coach has also praised the performances of striker George Thomas and defender Cian Harries after the first defeat of the season...
Coventry City Under-18s coach Jason Farndon has stated the defensive performance against Millwall is one the club 'will not accept'.
The Sky Blues lost their first game of the season at Millwall following an incredible eight-game unbeaten start to the 2014/15 season.
Having only conceded seven goals throughout the entire season prior to the Millwall, City conceded five against the London side.
The City Under-18s coach believes all the goals City conceded were preventable but was also quick to praise the performances of striker George Thomas and defender Cian Harries.
Farndon said: "We defended very poorly. All the goals we conceded were easily preventable and if we're going to have a successful season, we need to be better in defence and win our battles.
"We took the goals very well but I wouldn't say it is complacency. These are young players so these days happen. There were too many of our players who were not up to their usual standards.
"It was a performance which we will not accept at this football club. On the positive side, George Thomas was outstanding and he took his goals very well.
"Cian Harries had the best game I've seen him play, really maturing into the role and he's developing into a really good left-sided central defender."
City welcome Ipswich Town to the Alan Higgs Centre next week as they look to recover from their first defeat of the season.
Farndon believes the start to the season gives the Sky Blues a great platform to build on and hopes some of the Under-18s do well for the Under-21s tonight at QPR.
He added: "We've made sure we haven't got carried away with the start to the season we've had. We've always looked at what we can do better.
"It was a start to the season we didn't expect to have at this club and it mustn't be forgotten that it gives us a great platform to build on.
"Some of our Under-18s will feature tonight against QPR for the Under-21s and it will be another great experience for them to respond quickly.
"It will be a tough game for them but another chance for the lads to impress Darren Murray and the gaffer."