Tottenham are pulling out all the stops to try and beat Premier League rivals Southampton to the signing of Atletico Madrid defender Toby Alderweireld, sources have told ESPN FC.
Alderweireld, 26, enjoyed a successful season-long loan spell at Southampton last term and the St Mary's outfit are keen to make the move permanent.
As part of the loan agreement last summer, a deal was put in place to allow the Saints to sign the Belgian -- but Atletico are now hoping to sell Alderweireld to the highest bidder by cancelling the option Southampton had on the defender.
Southampton have the option to sign Alderweireld for £5.6 million -- but that can be over-ridden by a £1.5 million penalty clause which Atletico can pay to Saints to activate and then sell him to Spurs.
Atletico are willing to let Alderweireld move as the former Ajax man does not figure in Diego Simone's long-term plans at the Vicente Calderon, while the defender said in May that he would favour a move to the Premier League.
Southampton remain hopeful of striking a deal to keep Alderweireld, but now Tottenham are aiming to steal a march on them by luring the player to White Hart Lane.
Spurs boss Mauricio Pochettino is thought to have made Alderweireld one of his top targets this summer as he looks to pair with him with Belgian teammate Jan Vertonghen in a new-look defence.
Spurs are so determined to try and thrash out a deal with Atletico that chairman and chief negotiator Daniel Levy is flying out to Spain in a bid to secure the Belgian's signature.
Southampton are refusing to give up on the battle for Alderweireld, and it could come down to whoever the Belgian wants to join if the two clubs agree deals with Atletico.