Elena Lashmanova has won gold in the 20km for Russian Federation in a world record time of 1:25.02.
Reigning champion from Beijing Olga Kaniskina looked to have the race sewn up after leading the entire way, but Lashmanova finished superbly to take gold.
Lashmanova timed her race perfectly, sitting eighth after the first four kilometres before steadily moving up the field and reduced a 43-second deficit from 10km.
Kaniskina's time was a season's best of 1:25.09 but lost a 17-second lead in the final 2km.
Bronze went to Qieyang Shenjie of China, who did well to steadily move through the field from 12th to third, and finished with a time of 1:25.16.
