The agent of Modibo Diakite admits Sunderland beat Inter Milan and Napoli for the former Lazio defender.
Diakite has signed for Sunderland this week on a Bosman.
Ulisses Savini told TMW: "The reasons why Inter, but especially Napoli, have not closed a deal for Diakité are varied and are not attributable to economic aspects.
"But Sunderland has been shown to take negotiations seriously. We are grateful and the player is happy to have become a player for them."