Mick Robinson was walking his nine-year-old mongrel, named Fletch, near his home in Bransholme when he was set upon.
He said: "I could see three dogs – a big, white scruffy thing and two black terrier types in the distance. None were on leads and I couldn't see any owners.
"I had Fletch on his lead. The white dog walked towards us while the other ones wandered nearby.
"There was no barking or any indication they were about to attack.
"Then, completely out of the blue, the white dog went for Fletch. He had him pinned down. The other two then got involved.
"All three were attacking Fletch.
"I was punching and kicking them, desperately trying to make them let go of Fletch. They were snarling. He was helpless."
Mr Robinson, who is a machinist, said a woman in a high-visibility jacket turned up and put the white dog on a lead before walking away.
He said: "I have no idea if the two black dogs belonged to this woman.
"I was more bothered about tending to Fletch than I was about running after the woman."
The attack happened at about 10.50pm on Tuesday in Malpas Close.
Mr Robinson called his local vets, who advised him to take Fletch, who was bleeding and in shock, to the PDSA in Brunswick Avenue.
"The vet had to use metal staples to close the biggest wound on his back," he said. "Other wounds were washed and covered.
"Fletch was also given some injection to help with the pain."
Mr Robinson was later required to take his pet to his own vet.
He said: "In all, I've spent £420 in vets' fees. I don't, for a minute, expect the owner of the dog or dogs that attacked mine to come forward and offer to pay the bill.
"But all I can say is that I certainly would. Fletch is not like that but if he lashed out and injured another dog, I would pick up the tab."
Mr Robinson reported the attack to police.
"If it's a case of dog-on-dog, the police are not interested," he said. "I was not hurt. In a way, I wish I had been injured – that way the owner might have been traced and action taken against her."
Mr Robinson says he hopes the owner reads his story and takes action.
"I have a three-year-old granddaughter," he said. "The dog might well have gone for her. Dogs should be kept on a lead when they're being walked in a street."
The owner of the dog responsible for the attack can call Mr Robinson on 07856 832051.
