West Ham chief Tim Steidten admits they beat Borussia Dortmund to the signing of Edson Alvarez last summer.
The former Ajax midfielder has shone for the Hammers this season.
Steidten recalled to Sky Deutschland: "He has a very big influence on our game. I'm very happy that Dortmund was perhaps a little slow and I had the chance to get him.
He is a super important player for us. He is a leader. An absolute leader.
"He's great."