The best ability is availability.
Proverbial

Take it one game at a time.
Proverbial 

Waterloo was won on the playing fields of Eton
Wellington

The Score Takes Care of Itself
Bill Walsh, Title of book by 

“Everyone has a plan until they get punched in the face.”
Mike Tyson

“You miss one hundred percent of the shots you don’t take.”
Wayne Gretzky