Germany's Anna Dogonadze snatched trampoling gold with a brilliant performance in Friday's final.
Canada's world champion Karen Cockburn, the pre-competition favourite, took silver, with China's Huang Shanshan taking bronze.
Britain's Kirsten Lawton went out of the qualifiers, finishing only 12th.
Reigning Olympic champion Irina Karavaeva of Russia had an even worse time, ending qualifying in 15th place, just one place off last.