Aitor Karanka explains exactly what makes his ex-boss Jose Mourinho “the best”

Jose Mourinho may be finding life a little tougher at Manchester United than he has perhaps been used to, but to his former assistant Aitor Karanka he is still the special one.

Ex-Real Madrid Karanka began working with Mourinho when the Portuguese arrived at the Bernabeu. One of his first acts was to appoint Karanka as his assistant. The pair worked together during Mourinho's time in the Spanish capital before the ex-Chelsea boss left and eventually returned to Stamford Bridge, while Karanka took over as Middlesbrough boss, guiding the Teesside club back into the Premier League. He will face his mentor for the first time in a competitive fixture on Saturday when Boro visit Manchester United, and ahead of the clash he was asked what makes Mourinho so successful. "It's a mix of everything: his knowledge, his character, his passion, his personality - he has a lot of things," Karanka said. [caption id="attachment_104799" align="alignnone" width="1024"] Jose Mourinho (C) and assistants coach Rui Faria (L) and Aitor Karanka during a Real Madrid pre-season friendly against LA Galaxy in 2010 (Photo by Kevork Djansezian/Getty Images)[/caption]   "The way that he prepares the game is the best; the way that he trains is the best; the way that he is in the changing room is the best, so it's a lot of things and for that reason, he is the best. "The best example is the relationship he has with the players when he leaves clubs. He has a really good relationship with them all. "For sure, the players always want to play, but he has a very good relationship with most of the players who have been with him because if he goes to Arsenal, you can see him with (Mesut) Ozil giving him a hug, or when he goes to other places, he has a very good relationship." Mourinho's United currently sit sixth in the table, 13 points off his former side Chelsea, who lead.