Lancaster County authorities said a 64-year-old Firth man was defending his Chihuahua when he stabbed a 94-pound bull mastiff.

The dog-and-man melee happened Saturday afternoon while Joseph Slack was walking his 4-year-old Chihuahua, Killer. 
Slack told sheriff's deputies that the bull mastiff broke loose from a chain and attacked his tiny dog.

Slack said he tried to stop the attack but couldn't. So he pulled out a pocket knife and stabbed Rocky the bull mastiff twice in the chest. 
Rocky let go of Killer and ran back to his owner's house.

Both dogs are expected to recover from their wounds.  Sheriff Terry Wagner said he has no plans to charge Slack for stabbing the larger dog.
 The bull mastiff's owner was cited on suspicion of having a dog at large.