He wanted to turn professional, but needed to prove himself first.
I need it to prove my place in the division.
"It gives us everything we need to prove what happened on D5."
"I've heard the question do I need to prove anything?"
You don't need an army and your own private world to prove that.
"He still needs to prove himself in this new job."
"You know what it is to need to prove yourself, even if you're the only one looking."
And that is why this team still needs to prove itself.
Europe still needs to prove itself on all these points which, in fact, form a whole.
They will need to prove this in the next few weeks.