Manchester United must overcome big-spending rivals Manchester City and PSG to sign Real Madrid star Cristiano Ronaldo.

The Daily Express says Ronaldo's future at Real Madrid has been the subject of frenzied speculation, with the Portuguese superstar claiming to be unhappy with life at the La Liga giants.

United's bitter rivals City were hoping to capitalise this and were believed to be plotting a double transfer swoop worth £134m Ronaldo and his team-mate Fabio Coentrao last month.

And PSG director Leonardo has admitted he is still open to the idea of Ronaldo joining the club.

He told L'Equipe: "Cristiano Ronaldo? Paris Saint-Germain have become a club where anything is possible.

"When we are discussing a possible transfer for a player like Cristiano Ronaldo, there are only four or five clubs that can be taken into consideration. Paris Saint-Germain are one of those clubs."

Ronaldo hit another hat-trick for Real earlier this week in their 4-0 thrashing of Celta Vigo in the Copa del Rey to take his tally for the season to 28.