Sevilla suffered a major setback when Alexis Ciria signed for Real Madrid's youth academy during this year's winter transfer window.
Advertisement
Advertisement
The Andalusian club have now reacted by securing another of its prized talents, Guillén.
Sevilla doesn't want another departure to Madrid and has renewed his contract, raising his buyout clause to €20m.
The 17 year-old's deal now runs to 2027.