In what was always expected to be a two-horse race for gold Kashirina drew first blood, completing a 151-kg snatch lift that surpassed her own previous world record by three kgs and gave her a five-kilogram lead at the halfway stage.
But Zhou overhauled her with a superior performance in the clean and jerk, where she lifted an Olympic record 187kg that also gave her the world record combined total of 333kgs.
The packed crowd inside London's ExCel arena roared as Zhou approached the platform to set the new world record, screaming back at her as she shrieked in preparation for her lift.
But a demure and bespectacled Zhou smiled later as she told reporters that far from a war cry, she was actually saying 'Relax'.
"So I can lift the weight, relaxing," she said.
In the end, her approach worked as Kashirina's team were dragged into a tactical game of cat and mouse that backfired when she was unable to complete an ambitious final attempt in the clean and jerk.
"My job here is just to go onto the floor and do the lifting. The rest of it can be determined by the coach, the head coach and the rest of the team," she said.
Failure on that final attempt at 187kg left her with 332kg, one kilogram behind Zhou's winning total, when a lift of 182 would, with hindsight, have been enough to win her the gold by virtue of her substantially lighter bodyweight.
Armenia's Hripsime Khurshudyan took the bronze with a total of 294kg that secured the first medal of the London Olympics for her country.
Zhou's win ends China's weightlifting participation in London on a high note, but a haul of five gold medals and two silvers from their 10-strong squad has failed to live up to the high standards set four years ago at the Beijing Games.
In Beijing the squad won eight golds and a silver.
"I can say we feel mission unaccomplished because the men's weightlifters missed two gold medals," Zhou said.
Nevertheless, the picture was somewhat brighter for the female contingent in the squad. Three won golds and only 17 year-old rookie Zhou Jun, competing in the 53-kg weight category, missed out.