Mata is enjoying his seventh season in the Premier League after joining Chelsea from Valencia in 2011, but he told Sky Sports that he still holds a candle for La Liga and dreams of playing there again (via Toby Gannon of The Sun): "I don't know what will happen. I've been asked before, and I don't know. I've been here six years, and I am happy in England. But I love Spain still and always follow La Liga from here. I would like to play again back at home."
Mata is under contract at Old Trafford until the summer of 2018, and he believes he has unfinished business in England before he thinks about heading back to his homeland.
Despite playing in an exceptional Chelsea outfit and winning the Champions League in his first season with the club, Mata has never tasted Premier League glory.
He admitted to Sky Sports that he wants to add that notch to his belt (via Gannon): "I would love to win it. I have been lucky enough to win so many trophies already. For me, it's very important not to relax as a professional footballer and think I've won trophies with great teams and that is success. It is about always getting hungrier, trying to improve and trying to be better."
The 28-year-old has played a big role for Jose Mourinho's side this season, scoring and creating goals. His tally of five goals and two assists this term have made the Premier League's most lethal midfielder since his arrival in 2011, per FootyAccumulators:
Mata was in line for a new four-year deal at Old Trafford at the start of the campaign, per Steve Stammers of the Daily Mirror, but nothing has yet materialised.
Elsewhere, United are reportedly set to enter a transfer battle with neighbours Manchester City for the services of AS Monaco's Djibril Sidibe.
French outlet Le10Sport reports that the Manchester clubs have taken notice of Sidibe's strong defensive performances in Ligue 1 this term and are interested in bringing him to the Premier League (via TalkSport).
Sidibe is a versatile full-back who can operate on the left or right side of the back line, while his exciting pace makes him a threat going forward.
Manchester United have turned their fortunes around under Mourinho, but they're still a long way off the pace set by Chelsea at the top of the Premier League.
United take on Watford on Saturday, looking to close the gap on the Blues and continue their charge for a UEFA Champions League place.