The Football Association is refusing to admit it was wrong not to use VAR in all of the weekend's FA Cup quarter-finals.

Swansea's Liberty Stadium became the first ground to trial the system for the Premier League in 2017, and it was the South Wales venue that was the scene of controversy on Saturday as Manchester City fought back from 2-0 down to beat the Swans 3-2, with their last two goals likely to have been ruled out by VAR.

At the start of the season, the FA said it would continue its trial of VAR in the cup but only at current Premier League grounds, as many English Football League stadiums do not have the capability to provide it yet.

While that is understandable from a consistency point of view, several pundits have pointed out it does not make sense if you are trying to ensure the best standard of refereeing in the world's oldest cup competition.

It is clear from a statement issued by a Swansea spokesman on Saturday that the Championship club was surprised by VAR's absence.

"We are in the dark ourselves over the non-use of VAR here and that it would only be used in Premier League stadiums," he said.

"That seems a bit strange considering we were there for seven years and all the technology is placed here to accommodate it."

That sense of grievance becomes even more understandable when you consider that Swansea arranged a game between their academy and their under-23 side for the Premier League's first look at VAR in October 2017.

Former Premier League referee Mike Jones was in the VAR truck, with several top-tier referees observing.

The man in the middle that day was Andre Marriner, who was also in charge on Saturday and who could have used VAR to spot he was mistaken in awarding City a penalty for a trip on Raheem Sterling, and to correct his assistant referee's failure to see Sergio Aguero was offside in scoring the winner.

To add to Swansea's dismay, VAR was in operation at the Liberty Stadium when they met Spurs in what was an all-Premier League tie in the FA Cup's quarter-finals last year.

Some critics have also highlighted the fact VAR was used in the second leg of the Carabao Cup semi-final between Burton and City earlier this year, although it was installed to be consistent across the tie.

When asked if not using VAR in all four quarter-finals this weekend was a mistake, the FA declined to comment.

The system was used in the Watford-Crystal Palace and Wolves-Manchester United games but was not in operation in Sunday's Millwall-Brighton tie, won by the Premier League side on penalties, and who would have had a chance of seeing Millwall's opening goal chalked off by VAR.

It is understood the FA believes it was important to remain loyal to their initial commitment to only use VAR at Premier League grounds.

Calls for exceptions could have been made about games in the previous three rounds but clubs seemed to accept the rules were the same for both sides.

The lessons learned from this season's trial will be considered by the Professional Game Board for next season's tournament.

Both semi-finals and the final will use VAR as they are played at Wembley.