Megan Weaver was walking her Shih-tzu puppies Dash and Dodger in Silver Jubilee Park in Coseley when one of the animals was suddenly attacked by the vicious dog.
Dash, who was only seven months old, was picked up and shook by the rottweiler, which wouldn't let go despite every effort from Megan.
It happened after 6pm on Friday, and now police have launched an investigation to try and track down the rottweiler's owner.
"I'd seen the dog, but he was far away," the 20-year-old said. "I thought absolutely nothing of it.
"Then the lead was tugged out of my hand. My dog was in the other dog's mouth.
"I was in shock at first. I didn't realise how bad the situation was. I was just pushing the dog. It was that heavy that nothing was working. I was shouting at the man, the man was shouting at his dog but it just wasn't going to let go."
In the middle of the struggle, the rottweiler let go of little Dash.
But in an effort to rescue her pet, Megan was bitten at the end of her finger by the rottweiler.
"Dash was still alive then. He moved his head. I went to grab him, but as I did, the rottweiler pulled forward and nipped at the end of my finger. It took my acrylic nail off. If my hand had been any further forward it would have been a very different story."
The rottweiler picked up Dash again. When Dash was freed again, he was dead.
"I was in complete shock," Megan said. "My first thought was to run to the vets, but I soon realised he was dead.
"I phoned my family. I phoned the vets, who come and put a blanket over him. Then my uncle phoned the police."
The horrifying attack has left the family devastated, and Megan says they are desperate to find the other dog's owner.
"I hope he realises what he's done," she said. "I hope he feels sorry for Dash. I wish he could see pictures of my little brother crying. I wish he could see what he's done to my family.
"He shouldn't have a dog. I wish he'd give it to a better owner."
Megan, who lives in Coseley, said she was grateful that so many people had shared her story.
"It's amazing how many people have shared it and have been messaging us asking if there's anything they can do.
"There were a good few people going out on the night to see if they can find the man.
"I'm thankful everybody is being so supportive. Hopefully we find him."
A spokesman for West Midlands Police said: "Police are investigating after a dog was attacked by another dog in Silver Jubilee Park.
"Sadly the dog died as a result of the injuries received at around 6pm of Friday 25 October.
"The dog walker also received minor injuries to her hand.
"The attacking dog was believed to have been a Rottweiler type and was with its owner at the time."
Anybody with information is asked to call 101 quoting crime reference number 20DY/253675R/19.