Ander Herrera says he made the move to Manchester United thanks to his former Athletic Bilbao coach Marcelo Bielsa.
The midfielder arrived last week from Bilbao.
"My best position is number eight," said Herrera to the Manchester Evening News.
"With Bielsa I played six, like Sergio Busquets at Barca, eight like Iniesta and Xavi, and as a 10. Bielsa said I could become one of the best players in that position."
His versatility appeals to United, but he has to thank Bielsa for making him the player he is.
"He's the most original, different, singular, person that I've ever met," says Herrera.
"He's got an amazing mind. He has an incredible intellectual capacity for football. Nothing is ever left to chance, everything is studied to the finest details.
"He knows what every player can and can't do. He makes sure that everyone is on their toes. I've seen him speaking to the groundsman for 45 minutes. I'm sure he would have studied grounds keeping before that chat.
"He demands of others what he demands of himself. I've never seen a coaching staff work as hard as with him. He'd go crazy if a pole was half a metre the wrong way.
"I once had my feet on a chair. He came up to me and kicked the chair away. 'Do you see me with my feet up?' he asked.
"You've really got to like football a lot to put up with him. I'm lucky as I love football. I watch videos. Others just like to play.
"They really suffer under Bielsa. I was two years with him and always in the starting XI. 54 games with a groin strain in that season I played United. I'm thankful to him, but I really enjoyed my days off."
