Hi... What does "all evidence to the contrary" mean?!
The Spain Under-21 international kept a clean sheet at Craven Cottage and pulled off some stunning saves to once again prove his quality. Despite EVIDENCE TO THE CONTRARY, the media continue to CAST DOUBTover the youngster's grip on the goalkeeper's position at the club.
Cast doubt means doubt?! Or it has something more?!
Cast doubt: to cause someone or something to be doubted. The police cast doubt on my story.... In this example I think it just mean doubt but according to its definition it must has something more!

Question

Answer

"Despite evidence to the contrary" means that something has happened to show that the youngster will keep his position.

"Cast doubt" is active.  There are people working to undermine confidence in the youngster.

"Doubt" is passive.  There are people who do not have confidence in the youngster, but they are not trying to make other people doubt him.

Answer

EVIDENCE TO THE CONTRARY - Essentially means evidence which supports the other idea (or opposite idea).

Cast is a verb: Essentially means you are throwing it on something or someone. Example: The sky cast rain on us. 
So when you cast doubt you essentially labeling something as doubtful which is perceived by everyone. It plays some type of influence factor to its peers. If you just doubt something then it just affects you.