Sancho has become Borussia Dortmund's prized asset since joining the club from Manchester City's academy in 2017.
His rise to prominence was swift and consistent high-performance has seen his transfer market value rocket.
Manchester United have long been linked with the 19-year-old and it's widely reported that he tops their wishlist.
However, the rest of Europe's elite have been circling and pose a threat to United's plans of acquiring the Englishman.
Real Madrid have now emerged as serious contenders for Sancho's signature and won't hesitate to gazump United, according to the Daily Mail.
Madrid were reportedly keen to sign Sancho when he was leaving Manchester City and have kept tabs on the teenager ever since.
Sancho has twice been on the Golden Boy shortlist and is regarded as one of Europe's biggest talents.
Dortmund are thought to have accepted they will lose their star player next summer and are hoping to receive a fee in excess of £100m.
The news of Los Blancos renewed interest in Sancho will worry United, who were reportedly already fighting off Paris Saint-Germain.
And unless the Reds can qualify for the Champions League this season, a feat that looks less and less likely, they will struggle to lure the Londoner to Old Trafford.
To further complicate matters, Manchester City have an option in place that would allow them to match or counter any offer Dortmund accept for Sancho.
An investigation into a possible payment made by City to Sancho's agent in 2014, when he moved from Watford to Manchester, was concluded by the FA recently and found no wrongdoing.
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