An elite long-distance runner who last year qualified for the 2020 Olympic marathon trials has been viciously attacked by a pit bull mix named Taco in Texas.

Caitlin Keen, 26, was running on Fort Worth’s Trinity River Trail on Sunday when she says an off-leash dog wearing a puffy camouflage vest began to chase her.

Despite being a top-tier runner who won Cincinnati’s Flying Pig Marathon last year, Keen was unable to outrun the 62-pound Taco.

Dogged pursuit: Runner Caitlin Keen, 26, who qualified for the 2020 Olympic marathon trials (pictured), on Sunday was attacked by a pit bull mix in Fort Worth, Texas

This is the 62-pound pit bull mix named Taco that chased down and attacked Keen

The top-tier athlete suffered multiple bite marks running down the right side of her body (pictured in hospital)

‘Before I knew it, the dog had jumped up on me, grabbed my arm, pulled me to the ground,’ a bandaged-up Keen told KTVT. ‘I got up and tried to sprint away. It's a lot faster than I was, unfortunately.’

Keen, a graduate of Southern Methodist University who now works for an insurance company, suffered multiple gruesome bite marks from her right shoulder down to her buttocks.

Tyler Caviness, who was walking his two dogs along the trail at the time and witnessed the mauling, came to Keen’s rescue, as did a fellow runner who hurled rocks at the pit bull mix to scare it off.

Caviness managed to grab Taco by his collar and sit on top of him, as NBC DFW reported.

Doctors could not stitch up Keen's wounds inflicted by the dog for fear they get infected

Bloody aftermath: Keen later tweeted at the athletic gear company Lululemon, asking to replace her favorite shirt that was shredded by the dog during the mauling

’I mean, I'm lucky I'm alive,’ Keen said. ‘I'm lucky I had two people walk up at that same time because I don't know what would have happened.’

Taco’s owner was nowhere to be found at the time of the attack, but Keen told WFAA she arrived later and showed little remorse for what her dog had done.

Taco was taken away by staff from Fort Worth Animal Control and placed in quarantine.

The dog will remain in the city animal shelter for at least 10 days until a decision is reached concerning its fate. The pit bull's owner said she wants her dog back.

According to animal control, Taco does not have a history of biting.

Keen won Cincinnati’s Flying Pig Marathon last year (left), but she could not outrun the 62-pound Taco the dog

Keen, who was a star runner at SMU, plans to continue her training for the February 2020 Olympic trials in Atlanta

Meanwhile, Keen has been left to nurse her injuries. Doctors who treated her could not stitch up her wounds just yet for fear they would get infected.

Keen, who was a star runner at SMU, plans to continue her training for the February 2020 Olympic trials in Atlanta and is determined to return to Trinity Trail.

‘This isn't going to stop me from doing what I want to do,’ she told the local NBC station.