As dramatically as he had entered the Tour last year, when he won the corresponding event to take the yellow jersey into the first stage, so Britain's big hope, and the favourite to win the 7.3km time trial, made his exit in the arms of his Gan team manager, Roger Legeay.
He smashed into the spectator barriers as his bike skidded on a slippery descent after he had executed a U-shaped turn. He could hardly stand after his machine had nearly skidded under his team car but he was helped back on to it and twice tried to continue along the route but could not pedal. He coasted to a stop, his face twisted by a grimace of pain.
He dismounted and rested against a barrier with his head in his arms, before Legeay gently lifted Boardman and carried him to a waiting team car. He was taken to hospital and after a preliminary examination was last night expected to be flown to Britain for an operation that will be carried out today.
"It's going to be very difficult for Chris," Legeay said prophetically before the start, expressing the hope that his rider would be wary of the early bends.
Boardman was careful, particularly after his line through one corner took him too close to a barrier. Then as he started the downhill stretch to the valley, he crashed, and with him went a dream.
After the triumphs of the last three years in which he has become an Olympic champion, a world record holder, enjoyed his debut in the Tour and won two world titles, everyone was looking for the next achievement.
A string of time-trial successes leading up to the Tour, particularly one in which he beat Miguel Indurain, the four-times Tout de France winner had driven the hype that surrounded the North Wirral rider higher.
Once the miserable news spread quickly to the other contenders waiting to race, caution took over from ambition. The Frenchman Jacky Durand, who had completed the course early on, before the rain had taken hold, was left as the surprised winner of the event.
His compatriot Thierry Laurent was two seconds behind and another Frenchman Francis Moreau, a team-mate of Boardman's, one second behind him. All the first 18 finishers completed the course early.
Durand, who 24 hours earlier had learned that his Castorama team was to be disbanded at the end of August, had not planned to be part of the celebrations following the time trial.
"I was planning to watch the real race on television in my hotel, but when I saw the rain I started to believe that I had a slim chance," Durand said, after winning in the town where his team boss, Cyrille Guimard, had sprinted to victory 23 years ago.
He was sympathetic, though, to the plight of the British rider: "It's too bad for him," he said. "I would have preferred to see him win, rather than see something like that."
"I've never seen anything like it," said France's Thierry Marie, a specialist of the short time trials of the conditions.
The population of this town increased five-fold as 250,000 risked a soaking to watch the drama of the Tour and instead were provided with a soggy result with many normally no-hopers filling the top placings.
With 3,538km in front of them, Indurain of Spain, the Swiss Tony Rominger and the Russian Evgeny Berzin played safe. Indurain, who will equal the number of Tour wins enjoyed by Eddy Merckx, Jacques Anquetil and Bernard Hinault, if he is successful this year, was not even in the top 20 finishers in a discipline that he would regard as his forte.
Rominger was 26 seconds slower than Durand, and Indurain took 31 seconds longer than the winner to complete the course.
The desire for prime-time television gave the Tour its latest finish in 82 years with Indurain finishing closer to his bed-time than he would have preferred.
Rominger warned that riders would not be able to rest because they would still be highly nervous from such a short, sharp race.
"I may not sleep until two or three in the morning, and then we have a very difficult stage," he said, and now the untimely departure of Boardman will add to the tossing and turning throughout the hotels of Brittany.
The Tour's director, Jean-Marie Leblanc last night defended the decision to start the Tour with a prologue late in the evening for the first time since 1967.
"We could have raced in the afternoon and still have had a storm. I'm sorry for Boardman but professional cyclists know full well they have to ride in the rain," he said.Reuse content