Marisa de Aniceto, of France, who was placed only seventh with two events remaining of the heptathlon, snatched the gold from her rivals with an outstanding javelin throw followed by a piece of tough running at the end of the two-day test of the world's top youth all-round athlete.
De Aniceto placed third in the final heat, but her 2min 16.36sec effort earned her enough points, 874, to just see off the late charge by Germany's Sarah Kern.
Kern, true to form as a tall and elegant middle distance runner, stormed around the track, going through the bell in 61.34sec and finishing well clear of her rivals in 2:11.92, collecting 937, but putting her total just 13 points short of her French rival.
The bronze medal was won by Marina Goncharova, of Russia, who had held that position through much of the two days, only to lose ground in the penultimate event, the javelin, and slip back to seventh before the 800m run. But there, her 2:15.22 effort in Kern's slipstream did enough for her to leapfrog Jailma Sales de Lima, Gayle Hunter and Yuliya Tarasova and get back on to the medal podium with a two-day total of 5338.
In one of the closest contested multi-events in international competition, seven women went into the final event of the heptathlon separated by just 136pts.
The unlucky ones to miss out on medals included Sales de Lima, from Brazil, who ended with a lifetime best of 5319pts, as did Jessica Ennis, the leader for five of the seven events.
Ennis broke through 5,300-point barrier for the first time to finish fifth with 5311, and to ponder what she might achieve were she to learn the technique to throw the javelin.