The maths is simple - Kiwi 470 women's 470 pair Jo Aleh and Olivia Powrie must beat their British rivals in the final medal race to win Olympic gold.
The duo started today with a four-point lead over Hannah Mills and Saskia Clark, and doubled that with a second placing in the first race of the day at Weymouth, while the home crew could only finish eighth.
But a disastrous 18th-place finish in Race Two meant that they had to count an earlier 10th-place finish in the regatta, while the British pair - second in the last race - were able to ditch their worst performance - an eighth place - and draw level on points with the Kiwis.
Both crews have 33 points and whoever finishes ahead in Friday's double points medal race will take the honours.
The losers are assured of the silver medal, as neither boat can be caught by the crews behind.