Middlesbrough manager Aitor Karanka has highly praised Chelsea boss Jose Mourinho by describing the Portuguese coach as the "best" in world football.
Karanka, who took on his first senior managerial stint at Middlesbrough last year, worked as Mourinho's assistant coach during their three-year stint at Real Madrid.
"He is the best coach in the world," Karanka told newspaper ABC. "He has shown it, and tactically he is a hundred steps ahead of the others.
"At Real Madrid he made excellent tactical plans. When we had to make changes, his revolution was unique."
Mourinho's Chelsea side currently hold a four-point lead at the top of the Premier League table, while Karanka and his Middlesbrough team sit third in the Championship.