Watford’s 3-1 win over Manchester United earlier in the season is valuable but will have little impact at Old Trafford, according to head coach Walter Mazzarri.

The Hornets stunned United at Vicarage Road in September to record their first win over United in 30-years.

However, tomorrow’s hosts are a much-changed side from the one which showed early season frailties and enjoy a 15-game unbeaten Premier League run.

They have lost just three league games all season, and Mazzarri says this adds significance to Watford’s triumph, despite admitting Jose Mourinho’s side have improved dramatically.

“I want to underline, especially that if they lost only three games in the whole season, and one of them is against us, then this gives great value to our victory,” Mazzarri said.

“We met them in another part of the season. The season is very long and I said after that game that a great manager like Jose Mourinho was going to do well with Manchester United.

“They come with 15-games with consecutive positive results where they have had eight victories. This tells you a lot about who we are going to play against.”

After back-to-back wins against Arsenal and Burnley, the Hornets find themselves in the top 10 and could climb to ninth with a victory tomorrow.

Mazzarri is aware of the challenge facing his side, but feels taking a positive result from the match would provide evidence of how far the club have come.

“In their last game [against Leicester City] we have seen a team that not only had a great performance but one that is in a great condition as well,” he said.

“It (winning) would mean a lot and would mean that we have finally made the step forward that we are looking for in terms of technical quality. It would mean that we can make a result against any team.”