#6 Samuel Eto'o

It feels weird to see how Los Merengues let Samuel Eto'o slip through their fingers for just £4.4 million to Mallorca. Any of Real's doubts regarding the eagle-eyed Cameroonian may have been cleared, looking at the host of trophies he amassed after leaving them.
In his prime, Samuel Eto'o established himself as one of the strikers you would rather avoid playing against, thanks to his silky finishing skills. He became an integral part at FC Barcelona and haunted his former club on multiple occasions.
Eto'o replicated his Barcelona success at Inter Milan and had a relatively efficacious Champions League career, winning the competition thrice. He also claimed the FIFA World Player of the Year Bronze award in 2005.
Adding to the regret, Florentino Perez will also rue the fact that Barca poached him from under Real Madrid's nose.