A disconsolate Andrew Musgrave failed to match his own expectations as he went out in the quarter-finals of the cross country sprint at Sochi 2014.
The 23-year-old Brit felt he was a good match for the tough, hilly course and had recently taken a surprise win at Norway's national championships.
But he finished last in his quarter-final, shuffling forlornly across the line with the race a lost cause.
"I skied absolutely terribly badly today," Musgrave told BBC Sport.
"There is no other way to describe it. It's gutting. I picked the wrong day to ski slowly."
Norwegian skier Ola Vigen Hattestad won the sprint title ahead of Sweden's Teodor Peterson.
Less than a month earlier, Musgrave had beaten Hattestad into second place in the Norwegian national trials for these Games.
Norwegian experts had suggested the Scot could reach the Olympic podium after that win, but his form deserted him on the slopes above Sochi.
Musgrave still becomes the first British man to reach the quarter-finals of an Olympic sprint contest - but that result offered no consolation.
"In Norway I felt awesome, my shape was where it should be," he said.
"But last week, racing in Italy, I didn't get through the prologue (qualification round) there.
"I thought it was because that was a flatter, easier course and I'd be fine here. But I was pretty-much rubbish, I don't know what went on."
Norwegian broadcasters were at a loss to explain Musgrave's performance, suggesting that conditions - though slushy and soft - should have had no more impact on the Briton than any others.
And Musgrave said he had felt no additional pressure since his rise to prominence with January's victory.
"I don't really notice the pressure so much, I don't think that had anything to do with it," he said.
"It definitely wasn't nerves, I just didn't have a good day today.
"There are four years until next time. That's a bit hard to swallow at the moment."
Musgrave finished the event in 29th place. Britain's best-ever cross-country finish was Tom Cairney's 28th in the 50km race in 1956.
Maiken Caspersen Falla won the women's event for Norway - the country's 100th Olympic medal in the sport - while GB's Posy Musgrave finished 42nd.
Andrew Young and Callum Smith were 42nd and 62nd respectively for GB in the men's event.