Aston Villa manager Carla Ward said it was a “terrible mistake” that led to a potential breach of rules by using a player who was ineligible to play in the Women's League Cup.
soccer association under investigation After Noel Maritz played in the 7-0 win over Sunderland.
The Swiss defender played for Arsenal in the previous round Join the villa.
“We need to take collective responsibility for how this happened,” Ward said.
“First and foremost as a club we understand that a frankly terrible mistake was made and there has been an internal discussion and investigation into how it happened.
“We need to make sure we have the right processes in place to ensure something like this never happens again.”
The quarter-final draw was due to be broadcast live on the BBC on Friday, but was postponed pending an investigation by the FA, which referred the matter to an independent tribunal.
Barnsley is Banished from the men's FA Cup For using a player who was ineligible to play in a first-round rematch victory at non-league Horsham in November.
Villa is being investigated for “suspected violation of Cup Rule 8.19.”
Wednesday's 7-0 win took them through Group A ahead of second-placed Sunderland and secured them a place in the quarter-finals, but their fate now depends on the court's decision.
In a similar case, Reading were removed from the 2014 League Cup squad and fined £50 for using Bonnie Horwood, who had played three games for Watford.
The five League Cup group winners will advance to the knockout stage, alongside the top two teams in second place, determined on points per game basis.
Manchester United finished second in Group D and qualified for the knockout stages with 2.25 points per game, but Tottenham's 2.5 points from Thursday's win over Southampton only put them ahead.
However, if the result goes to Sunderland and Villa are not handed a harsher penalty, Villa would be level with United on points but ahead on goal difference, and Sunderland would win Group A.
Asked about the impact on Manchester United and his thoughts on the situation, manager Mark Skinner said on Friday: “My understanding so far is that the matter will go to court and we will see the outcome. That's all. I think that's all we know.”
“The fact is, I don't think we have a say, even if it could directly affect us. “I hope that the right decision is taken and that it is not to the detriment of Manchester United. I just want to repeat what I said last night.”
“We did everything we could to qualify from the most difficult group. We hope that the right decision will be made without reprimanding Manchester United.”
This latest situation in the villa comes after Arsenal beat Everton 2-1 This match in the Women's Super League was the only match in that division not to be broadcast live on television due to a scheduling error.
Asked how damaging these mistakes were given the spotlight on women's football, Ward added: “Right. Look, we can't escape the little points like the ones you mentioned. Of course we want to grow women's football.”
“Of course, you can't help but hear about mistakes. Mistakes are made by humans. It's not limited to the women's game because there are humans at work in the men's game as well, but you said So, the important thing is to keep growing the game.”
“I've talked about it a lot. It's about building the structures and infrastructure and making sure all the women's games grow in the right way.”
Aston Villa face Manchester United in their next WSL match on Sunday (kick-off 12pm GMT).