Cristiano Ronaldo admits he could one day make a sensational return to Manchester United.

Ronaldo became a cult hero at United after enjoying six successful years under Sir Alex Ferguson.

The Portuguese winger moved to Real Madrid for £80million in 2009, but he still remembers his time at Old Trafford fondly.

Although he says he is happy at the Bernabeu, Ronaldo appears open to the possibility of going back to United in the future.

When asked about the possibility of playing for United again, Ronaldo told MUTV: "I love Manchester and you never know in football. Of course I'm happy at Real Madrid; it's my home, it's my club, but United treated me unbelievably, so you never know.

"I am still in contact with some people there because I had a good relationship with everybody - it was like my second family."

Under Ferguson, Ronaldo won three Premier League titles and one Champions League before departing for Real Madrid for a then world-record fee.

United flopped spectacularly under Ferguson's successor David Moyes, who led the team to seventh - their worst-ever finish in the Premier League era.

But Ronaldo thinks United are now destined for success under their new manager Louis van Gaal.

"I think Van Gaal is going to do a fantastic job," Ronaldo said in the interview, which was broadcast on the eve of United's friendly against Real Madrid in Ann Arbor, near Detroit.

"He's an experienced manager and I think he's going to do well for United.

"It will be a better season, for sure. I hope United come back like people know they can; they are always so strong and I'm looking forward to seeing them this year."