The summer signing from Manchester United has been superb for OM, helping to the top of the Ligue 1 table.
A pleased Longoria said at a function in Portugal: "For us, he is a player who makes the difference on a technical level. His behavior has been excellent since his arrival in Marseille.
"He has adapted very well and the result and the impact he has had for us during the first three days of the championship has been enormous."
Regarding the player's attitude, the Spaniard was very clear: "Everything they told me about him at Getafe is the reality that I see on a daily basis.
"We had all the information we needed and I think we were able to make the right decision."
He continued: "His arrival was very quick when we spoke about it with the coach. He already knew him and everything happened very quickly, even if there were obviously debates. We believed a lot in his talent and we are very happy with what he is.
"What he is already doing with us, his behavior is fantastic and we are very proud to have him among us in Marseille."