Great Britain's Hannah Mills and Saskia Clark are mathematically assured of a medal in the women's 470 sailing class at London 2012.
The pair have amassed a large enough points margin after the end of the opening 10-race series to be sure that they will leave with at least a bronze.
Silver is also theirs as long as they are not disqualified or black flagged in Friday's medal race.
Mills and Clark now face a straight fight with New Zealand's Jo Aleh and Olivia Powrie for gold, with the pair level on 33 points.
On Tuesday, Britain's 470 men, Luke Patience and Stuart Bithell, secured at least a silver ahead of their medal race on Thursday.
Earlier, Great Britain's Stevie Morrison and Ben Rhodes saw their hopes of a bronze medal in sailing's 49er class end.
The Exmouth sailors came into the medal race six points off the bronze medal - the only podium position yet to be decided.
However, Morrison and Rhodes fell short in a tense race on the Nothe Course and finished fifth as Denmark's Allan Norregaard and Peter Lang secured bronze, while Australia's Nathan Outteridge and Iain Jensen wrapped up gold.