It was the manner in which the former Real Madrid assistant hit it off with Middlesbrough chairman Steve Gibson.
A legendary three-time Champions League winner whilst representing Real Madrid as a defender, Aitor Karanka - now 41 and in his first full-time role as a manager - has revealed the real reason why he decided to succeed Tony Mowbray in November, last year.
Karanka enjoyed a glory-filled playing career at Athletic Bilbao and Real. Once he hung up his boots, he was appointed assistant manager of Los Blancos by current Chelsea head coach Jose Mourinho, whilst also managing the Under-16 Spanish national football team.
Leo Percovich joined Karanka at Boro, but neither may have accepted the offer had it not been for the manner in which they bonded with Middlesbrough chairman Steve Gibson.
"Leo came from Houston and we were having dinner with Steve and [chief executive] Neil [Bauser]," began Karanka to the Gazette Live. "He left the table to come with us to our apartment. Leo thought that he was coming with us because he was in the same apartments.
"When we were together alone in the apartment, we both said that Steve is a gentleman. He came 200 metres just to say good night and that shows just what type of person he is. Someone had already told me about Steve so it wasn't a complete surprise. Even so, it was unusual for me, but even more so for Leo."
Karanka continued: "In football, you can find a lot of different personalities. The most important thing is that Steve is a normal person. In this moment, to be a normal person is a very good thing.
"Steve is a gentleman."
Middlesbrough are currently gunning for Championship superiority having collected 16 points from nine games and are the wrong side of a play-off place by goal difference alone.