Chinese head coach Xu Haifeng's decision to include out-of-form shooter Tao Luna in the women's 10-metre air-pistol event backfired when the Sydney Olympic champion finished a disastrous joint 38th yesterday.
Tao had gone into the competition as one of the clear favourites for the gold medal.
But her most recent form had been worrisome for Xu, who contemplated replacing the 30-year-old Olympic gold medallist 24 hours before the competition.
It was a decision he would regret as Tao was simply awful, scoring just 366 points in the qualifying round to finish joint third-last among the 41 shooters.
That score was lower than Hong Kong's Lo Ka-kay, who finished 34th on 371 points.
Only Carmen Malo of Ecuador and Francis Gorrin of Venezuela fared worse than Tao, whose defence of the Olympic title was among the worst in history.