I'm going with the rooster. Cats behave much differently in a hunting situation than they do in a fight-for-survival situation. If the cat got the drop and decided to engage, it would pounce and, unless it got a lucky first bite on the back of the neck, quickly find the rooster much more than it bargained for and run away at an incredible speed.
If the cat didn't get the drop, the rooster would chase it off without there ever being a fight. An angry rooster as big as you and bred and trained to kill would be absolutely terrifying.
Now, if the cat were rabid or somehow also trained to kill, that would be a different fight. I'd give the cat an edge in that one, though it would probably be a Pyrrhic victory.