A cycling fan visiting Adelaide for the Tour Down Under has described how he helped avert "carnage" at yesterday’s People’s Choice Classic criterium race when an inflatable arch collapsed as the peloton approached.

Not only did Ross Dobson help hold the arch aloft to enable the riders to safely pass under it – he also used his spare hand to catch a bike that was knocked off one of the team cars following the race, which is the traditional curtain raiser to the WorldTour race and includes the same teams.

Mr Dobson told ABC News that there was little time to react, saying: "I think they [the riders} were due in probably 20 or 30 seconds' time and the thing collapsed.

"I would say it was a generator failure or something along those lines, he went on. “It was falling onto the track and it was easy to see there was going to be some carnage at that particular point on the circuit."

The Canberra native, who is 6 foot 2 inches tall, vaulted a fence onto the road so he could hold up the arch. Some other spectators did likewise, as a photograph accompanying ABC’s report shows.

"I think there would have been a few injuries, they were fairly bunched up and it was probably seven or 10 laps from the end of it.

"Then the fun really began because the team cars were following with their bikes ... and we just weren't tall enough for those guys to come through."

One bike did get knocked off the roof rack it was on, but Mr Dobson explained that he ensured it didn’t get damaged.

"I caught that mid-air and I whacked that back on top of the rig and then I think enough people had sort of seen what was going on and they started to help dismantle the device," he said.

By the time the riders returned on the following lap, the arch had been taken down and the race continued, with Giant-Alpecin’s Marcel Kittel taking the victory.

Australian, good at catching and preventing collapses ... that sounds to us like decent credentials to make the tour party for The Ashes this summer ...