While cat fights are fairly common, its a good idea to try and keep your cat out of trouble, as even a relatively mild injury can become infected and form an abscess. If your cat has been in a fight and has clear marks of animal bites, ensure you make an appointment with your local vet to get them looked at.
If you see your cat in a fight with another strange cat, it’s important to be very careful in breaking it up, as you can quite easily get caught in the middle. It is usually sufficient to clap your hands and yell to cause the fighting cats break off their fight, and the other cat will usually flee. If they don’t break it off, the strange cat might be rabid, in which case you certainly don’t want to risk being bitten.