Although they were ranked in second heading into the medal race, the Kiwis had a tough battle on their hands to secure a podium finish.
The British crew of Saskia Clark and Hannah Mills had the gold medal stitched up ahead of the deciding race, holding an unassailable 20-point lead heading into the medal race. But with four points separating second through fifth position, any one of four crews were a chance of taking out the minor medals.
Team Jolly looked as if they might have to settle for bronze at the mid-point in the race, with the US pairing of Annie Haegar and Briana Provancha, who were just one point behind the Kiwis heading into the race, dominating early on.
But Aleh and Powrie played the conditions perfectly to roll over the top of the US, who ended up missing the medals altogether.
The French pairing of Camille Lecointre and Helene de France, who are the reigning world champions, took out the bronze.
That Team Jolly were even in a position to win a medal was remarkable.
Two disqualifications in their 10-race series saw the defending Olympic champions languishing back in seventh heading into the penultimate day of racing, effectively ending their chances of becoming the first New Zealand sailors to win back-to-back gold.
Despite the massive setbacks, the tenacious pair, known as Team Jolly, managed to fight their way back into silver position heading into the medal race after picking up two firsts and a third on the final day of qualifying races.
It brought Aleh and Powrie's record for the regatta up to four wins from 10 races. By way of comparison, the all-conquering 49er pair Peter Burling and Blair Tuke, won three of their 12 fleet races.
Yachting New Zealand have now met their target of three medals in Rio, after Sam Meech took out bronze in the Laser class on Wednesday, while Peter Burling and Blair Tuke are assured gold in the 49er.
Burling and Tuke will confirm their gold medal 49er class later this morning.
The four-time world champions locked in the gold medal in Wednesday's final qualifying race, extending their lead in the series out to an unassailable 34-point advantage heading into the medal race.
With Burling and Tuke assured of the gold medal, all eyes will be on the battle for minor medals as the Australian crew of Nathan Outteridge and Iain Jensen, who beat the Kiwis for gold in London four years ago, ranked in the bronze medal position, just three points behind Germany's Erik Heil and Thomas Plossel.
The Olympic sailing regatta will wrap up with the medal race in the 49erFX fleet, in which Kiwi pair Alex Maloney and Molly Meech are a chance of securing a medal in a wide open race.
Maloney and Meech are sitting in fourth heading into today's deciding race, but with just one point separating the top four, which ever crew finishes in front takes out gold.
