Juan Mata
Juan Mata has scored five Premier League goals this season Reuters

Former Chelsea star Juan Mata has claimed he is working with an optimistic attitude to be ready to "contribute to the team at any time" despite his struggles at Manchester United under manager Louis van Gaal.

The Spain international moved to Old Trafford during the January transfer window in 2014 after then manager David Moyes agreed to break the club's record transfer fee by paying £37.1m ($54.6m) to the Blues to secure his services.

Even though the 26-year-old was Chelsea's player of the year during his first two seasons at Stamford Bridge – winning the Champions League, the FA Cup and the Europa League – he fell out of favour with manager Jose Mourinho in the first half of the last campaign and was forced to look for an exit.

Mata quickly adapted to life under Moyes and scored five Premier League goals at United in the second part of last season. However, the midfielder is now in a similar situation to the one he had with Mourinho after Van Gaal recently opted to used Marouane Fellaini ahead of him for the playmaker role.

Mata has not begun a game since scoring the opener in the FA Cup 3-0 victory over Cambridge United on 3 February. He has started on the bench in the last six Premier League games and was an unused substituted in the last cup games against Preston North End and Arsenal.

But the Spaniard has expressed a positive attitude about overcoming the situation in a Facebook Q&A with supporters.

When asked by a fan about his situation, he said: "I'm working in the same way I have always done, with the same attitude and the same passion. That's all I can do, I'm always optimistic and ready to contribute to the team at any time."

Meanwhile, the United star expressed his confidence with the team's chances to secure a spot in the Premier League top four in order to play the Champions League next season.

He said: "This is obviously our main objective until the end. Manchester United must always play in the Champions League, and we believe we´ll make it!

While asked about the game against Tottenham on 15 March, he said: "Hopefully is going to be a good result for us. I enjoy playing against Tottenham because i had some good experiences against them."