David de Gea came very close to signing for Real Madrid in the summer of 2015, however a deal fell through on deadline day due to paperwork complications.
The Spaniard ended up committing his future to United by signing a new four-year deal worth £200,000-a-week.
However, Real have resurrected their interest and could make a £55m bid for him in the summer.
And the Star on Sunday claim United could activate his current deal and extend it by a further 12 months.
David de Gea could earn around £300,000-a-week at Manchester United if he extends his contract
Jose Mourinho doesn't expect Real to use underhand tactics to get David de Gea
Manchester United player ratings against Watford
Sat, February 11, 2017
Express Sport brings you our Manchester United player ratings from their clash with Watford at Old Trafford
1 of 15
How did the Manchester United players rate during their clash with Watford?
We will be very direct. So they are one of the clubs that I am not worried about at all
Get Quotes on Home Insurance
It is thought should he pen the extension, he could earn around £300,000-a-week which would make him one of the club’s top earners.
Mourinho admitted on Friday he didn’t expect Real to use underhand tactics to try to claw De Gea away from the Red Devils.
He said: “With regards Mr Perez and his right arm, Jose Angel Sanchez, they are some of the people in football that I can say I did not just work for them and then it [the relationship] is over.
“So, if at the end of the season I want one of their players or they want one of our players, we will not do it through the press – we are going to exchange messages.
“We will be very direct. So they are one of the clubs that I am not worried about at all.”