That power isn't of much use if he can't catch the cat. As with all animals, some are better hunters/fighters than others. Most wild cats and domesticated outdoors cats are incredibly cunning while hunting/fighting, much like a trained hunting dog. They know what they can or can't do on targets bigger than themselves and they either flee or aim at weak spots, such as eyes and nose. A good paw strike at a dogs eyes can potentionally kill it and a good hit on the nose will make most run away in pain, no matter of size.
You'd be amazed of how much power a small tabby can produce with a punch, now add 1inch razor blades on the working end of that punch, not to talk about the speed they can dish those punches out with.
But again, it's all about the experience and mentality of the animals.
Edit: Also, a domesticated animal doesn't have anything to lose so they tend to be less careful and generally don't care if they get injured. It's not like they have to hunt for their food if they have a home to go to.