Manchester United new signing Juan Mata says cementing his place in Spain's World Cup squad was the primary reason behind leaving Chelsea for Old Trafford.

Despite featuring 20 times for the Blues this season, Mata has been a peripheral figure under Jose Mourinho this term in the club's big matches.

Mata sealed his £37.1m move to United over the weekend and is charged with inspiring an assault on qualification for the Champions League and says playing regular football prior to the World Cup was the chief motivation to moving to the club.

"It was really important because the Spanish squad is really difficult to get in," Mata said.

"I hope it is going to be a great chance for me to keep playing and be fit and show to the manager that I want to be there.

"Looking at the last six months I wasn't playing a lot, it is a new challenge for me. Sometimes in your career you need to clear your mind and take the chance you have.

"This was a massive chance for me to continue in England. That was the moment, that was the club.

"Man United is a massive club. In England it is the club with the most fans around the world. It is a big challenge for me. But I think everything is going to be fine, with the players that are going to come in the summer."

Reports have suggested that Mata's arrival at United will strengthen Wayne Rooney's future at the club, with the Premier League champions set to offer the England international a bumper new deal.

And Mata hopes he will be playing with Rooney who he describes as one of the country's best players.

"For me he is one of the best players in the history of this country," Mata added. "He can score, assist and come to the midfield to move the ball. I will try to find the gaps between the rival defences because I was used to doing this. This is my way of playing."