Locals tried to pull parts of the pile of cacti out of Diego Moreno's skin after the cyclist flew into the thorns during a race in Buenos Aires, risking his sight as he hurtled off the road.

He needed urgent hospital treatment but escaped life-threatening injuries after failing to spot what he described as a "crater" in a freak accident that was caught on camera.

“We were in a group of three cyclists," shaken Moreno is said to have told local media.

"I was the last one in line. I didn't see a hole in the asphalt and I fell into it.

"Thank god I was wearing a helmet and glasses and I didn't hurt my face and head. Because of the thorns, I could have gone blind."

More than 1.4 million people watched one version of a video showing Moreno gingerly stepping off the kerb while a group unsuccessfully tried to remove clumps of the cacti from his statuesque limbs.

"I backed into one of those playing golf in the desert a few years ago," said one sympathetic viewer on Twitter.