Federer was beaten by Nadal. If Andy Murray now reaches the final, Federer will drop to number 3 in the world.
You can read the sentence like this:
Federer (who could now drop to World No.3 should Andy Murray reach the final) was beaten 6-4 6-2 by the Spaniard.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.