Roy is impressed by Liverpool managing to secure Virgil van Dijk to a new contract. The veteran defender has penned a new deal to 2027.
Roy told of his fellow Dutchman: "His renewal is good news for Liverpool.
"After Maldini, Costacurta, Baresi and Tassotti, there haven't been many defenders stronger than others in football up to now. Since Virgil started playing with Slot, if possible he has improved even more.
"Because with Arne (Slot) he has found an organised style of football in a way that makes things much easier for him in possession, to play forward.
"The same can be said for the national team, with (Ronald) Koeman. That's why he has distanced himself from the other defenders. All he needs to win is the European Championship or the World Cup..."