Russian Elena Lashmanova powered to victory in the women's 20km walk at London 2012, breaking the world and Olympic record in the process.
The 20-year-old pipped her compatriot and defending champion Olga Kaniskina in a time of one hour 25 minutes and two seconds.
Kaniskina had to settle for silver despite leading for most of the race, Shenjie Qieyang of China took bronze.
Britain's Jo Jackson was disqualified for her technique in the fourth lap.
Kaniskina made the race around the London landmarks look easy, taking the lead almost immediately from the start.
Lu Xiuzhi went with her but even the Chinese athlete, who produced the fastest ever time by a non Russian back in March, found the pace tough.
Mirna Ortiz of Guatemala tried to close the gap in the third lap before her attempts of a medal were bought to a premature end as she was the first shown a red paddle and disqualified.
The only thing that looked like it could prevent Kaniskina from continuing her dominance of the sport was falling foul of the rules on technique but with the finish line in sight Lashmanova made her move.
She stormed past the fellow Russian to leave her in shock and having to settle for silver.