Juan Mata has backed Manchester United's first summer signing Ander Herrera to achieve success at Old Trafford.

The Spanish midfielder had a buyout clause of £28.4m with Athletic Bilbao and the 24-year-old paid his own release clause in order to join the Red Devils in the summer transfer window.

Herrera starred for United during their first pre-season fixture. The Premier League giants registered a crushing 7-0 victory over the MLS side LA Galaxy, where the Spaniard was the only player to play the full 90 minutes.

Mata was impressed with his compatriot's performance on his United debut. The former Chelsea star believes Herrera will contribute a lot for the Red Devils this season.

"He [Herrera] did great. I know him very well from our days with the Spanish national youth teams and he was very good tonight. I am very happy for him," Mata told United's official website.

"We have a good connection on and off the pitch and I think he will give us a lot of good things this season."

United's new manager Louis van Gaal played with a new system, with three central defenders at the back. Chris Smaliing, Phil Jones and Jonny Evans started, while other summer signing Luke Shaw and Antonio Valencia played as full-backs in the first half.

Mata is delighted with the United player's ability to adapt to the new system. However, the Spain international says there is still a lot of scope for improvement, both physically and tactically.

"We are all pleased with the result but we know this is just the first step. Some of the players have only been training for three or four days so we have more improvements to come, both physically and tactically," the former Chelsea midfielder said.

"But I think we had a good understanding of the new system and the football the manager wanted us to play."

"It was a good game for us. The manager wants us to play quickly with the ball in the middle, try to look for options and also play with width as well. That's what we'll keep trying to do," Mata concluded.