Olympic director Jez Fanstone and Kosinska's coach Dave Robertson have been impressed with how she has improved over recent months and are clear that this top 10 finish from her, within the Olympic test environment, is very encouraging.
"We are impressed with Natalia's performance; it's a big step up for her, her first medal race, and improving all the time," said Fanstone.
In the 49er skiff class, Peter Burling and Blair Tuke recorded a fourth and a win in their two races yesterday.
After 13 races the Kiwi pair lie in third place, five points adrift of Australians Nathan Outteridge and Iain Jensen who have been overtaken for the lead by Spain's Iker de Lizarduy and Xabier Fernandez Gaztanaga.
The 49er fleet will use tomorrow's scheduled rest day if possible with a view to complete the 15 race series before the medal race on Monday in Weymouth.
Andrew Murdoch, still leading the Laser event, will line up for his medal race overnight as will Jo Aleh and Olivia Powrie lying seventh in the Women's 470.