With seven gates demolished in the show jumping, plus a refusal, the Briton was out of contention even before the final discipline.
As they lined up for the cross-country race, Phelps was trailing Hungary's Laszlo Fabian, the man he beat last year, by 371 points.
Converted into time, this represented more than two minutes. 'He'll need a Harley Davidson,' Bryn Vaile said. The press officer, an Olympic gold medallist in yachting at Seoul in 1988, knew a loser when he saw one.
But Fabian lost out and it was Russia's Dmitry Svatkovsky who outsprinted Christophe Ruer, of France, to come home first, with Hungary's Janos Martinek third. France won the team title.
It had been a ferociously contested championship, the five sports all completed between 8am and 7pm, and when they lined up for the run only 99 points covered the first 10 competitors.
Earlier, the women's team gold medal was finally awarded to Italy after an agonising night of dispute. The Italians and Poles had each collected 15,352 points in Saturday's final and the novel idea arose of awarding gold medals to all six athletes.
The Poles accepted willingly, but the Italians refused point blank and pointed to the rule book, which officials had apparently overlooked. They had won three of the sports, the Poles two, and they were not going home with half a medal. The officials conceded.