Jarl Magnus Riiber's Beijing nightmare literally took another huge turn for the worse when he cost himself the chance of Olympic gold by skiing down the wrong route.

The Norwegian was on course to take the men's Nordic combined title on Tuesday when he held a lead of 44 seconds at the start of the 10-kilometre cross-country skiing race.

Riiber was the man to catch after putting himself into the gold medal position by topping the ski jump standings on the large hill at the National Ski Jumping Centre.

The 24-year-old only ended a spell of two weeks in quarantine the day before this event, having tested positive for coronavirus when he arrived in China.

Riiber endured another nightmare when he headed for the finishing line at the end of the first of four laps in the cross-country skiing finale, rather than starting another loop.

After realising the error he had made, Riiber turned back in a hasty retreat, but his advantage had been cut to barely 10 seconds.

He ended up finishing eighth as compatriot Joergen Graabak was crowned champion, and Riiber was left to reflect on a massive gaffe.

Riiber said: "It's not fun to show the world that I've maybe wasted a gold medal on that.

"It's a silly mistake, but on a normal day with that mistake as well I would be in the fight, I'm a good sprinter and I would fight for the gold anyway."

Asked about his physical condition following a fortnight in a hotel room, he said: "I like to say I am one of the best cross-country skiers on the normal day with good preparation and I showed that before that I can go fast (in) races."