John Bennett, 44, became the first casualty at Pamplona's annual running of the bulls fiesta on Sunday 7 July, when he fell and was crushed by runners as they fled from a charging bull.
Bennett, of Wolverhampton, said he nearly suffocated beneath a pile of people after an enraged bull turned on runners.
More than a dozen people ended up in a heap on top of him as the half-ton bull threatened to attack and sent people running for safety.
Bennett suffered knee injuries and was treated at a local hospital.
"I remember running and tripping over people who had fallen to the ground as the bull charged towards us. It was complete and utter chaos," he told the Telegraph. "I was crushed under people who fell on top of me. I felt my legs being twisted under me with all the weight.
"There was a terrifying moment when people on me were crushing my face to the ground and I couldn't breathe. A first aid person managed to grab my hand and pull me to safety under a fence. He saved my life. I was suffocating under the weight of the people I had on top of me."
Bennett, a gas firm worker and father of one, had travelled to the fiesta with four friends.
"It was the first time I've run and it will be the last. My wife Michelle knew I was coming here and pleaded with me not to run."
Doctors said he was lucky not to have suffered broken bones and would be discharged later in the day.
A 24-year-old Australian was also treated for bruising, as well as an American citizen who received treatment for a minor injury. A 36-year-old native of Pamplona with a minor injury was the only remaining casualty in the hospital by mid-afternoon, the government said.
The first run of the annual event, during which the crowds swell to more than a million in the Spanish city, lasted just over four minutes.
Fifteen people have been killed at the annual festival since records began a century ago.