Reguilon spent last season on loan at Sevilla and has now returned to Real Madrid. Despite catching the eye during his loan stint, Real Madrid are willing to let him go.
Manchester United are in talks to land the defender, but discussions have slowed due to Real Madrid’s insistence on a buy-back clause being part of any agreement.
Tottenham are now poised to rival Manchester United for Reguilon, with Mourinho an admirer of the Spaniard’s talents.
Mourinho will hope that he can tempt Reguilon to make the move to north London, rather than Manchester.
Spurs are already trying to sign one player from Real Madrid in the shape of Gareth Bale, with a loan deal for the Welshman eyed.
They will hope that a double raid on the Bernabeu can be completed, with both Bale and Reguilon setting sail for the Premier League.
Reguilon helped Sevilla win the Europa League last season and the Spanish side had been hopeful of re-signing him.