Manchester United midfielder Juan Mata has expressed his belief that VAR will be "good for football", but conceded that it still needs work after seeing a goal controversially ruled out during this evening's FA Cup clash with Huddersfield Town.

Mata was initially adjudged to have doubled his side's lead at the John Smith's Stadium when he rounded the goalkeeper and slotted the ball into an empty net, only for VAR to chalk the goal off after lengthy discussion which appeared to include inconclusive offside lines on the video replay.

Romelu Lukaku's brace ensured that the marginal decision did not have a major impact on the outcome of the match, but Mata admitted that there are some flaws which still need to be ironed out.

"It was important to get through and get to quarter-final and obviously our aim is to try to get to Wembley and win this cup again," he told BBC Sport.

"On the pitch I didn't know if I was offside or not because it was I think the line was very tight. I did what I had to do which was to score and celebrated. Then after I saw the referee speaking to someone and you look silly when the goal is denied.

"I'm up for VAR and I think it is good for football especially to make important decisions and make it a little bit fairer but it seems like today it was not a very clear the decision against us and me. The good thing was that it was not needed [the goal] because we won anyway but I think we all wished it was quicker. I celebrated and it didn't count."

United have now reached the quarter-finals of the FA Cup in each of the last four seasons.