Alonso 'an indecipherable character' - Costa

Former Ferrari technical director Aldo Costa has described Fernando Alonso as "a true great" but "an indecipherable character".

Costa replaced Ross Brawn as Ferrari technical director before being sacked in 2011. Having since joined Mercedes, Costa is now part of the team dominating the 2014 season and says he wants to retain the current driver line-up of Nico Rosberg and Lewis Hamilton despite his obvious admiration for Alonso's skills.

"I consider Fernando a true great when he is in the car, driving," Costa told Italian journalist Leo Turrini. "Out of the car, I was never able to understand him; to me he is an indecipherable character, an enigma. However he will not be coming to us at Mercedes, I do not see why Hamilton should want to leave a team like ours."

And Costa says the lack of recent success at Ferrari can be attributed in part to the way president Luca di Montezemolo has final say on all decisions.

"Strategic mistakes were made - I'm talking here about errors of vision - very serious ones. And of course they haven't always taken the best decisions regarding people.

"I'll give you an example: In 2008 we in the racing department put in a request to construct a new wind tunnel. We considered it essential to remain competitive. We were told that this was not the case and that there was no need.

"In Ferrari all the decisions, on strategy and people, have always been taken by the president, Montezemolo. To be fair, he took them when Ferrari was winning everything and he also took them when Ferrari stopped winning."