It reports that Ronaldo remains "unhappy with life in Spain" but says United's signing of Alexis Sanchez "has slammed the door on a potential return to Old Trafford."

Instead, the paper says it "understands Ronaldo would be open to move to Stamford Bridge in the summer."

The key could be Eden Hazard, repeatedly linked with Madrid, with the Sun saying Chelsea "could be tempted to let Hazard leave for the Bernabeu if Ronaldo was included in a deal."