GENEVA, Switzerland -- Tom Slingsby's Australia ended day one of the Switzerland Sail Grand Prix on top after mixed conditions led to a difficult afternoon's sailing.

A fourth-placed finish in the first fleet race, a resounding victory in the second and a third in the final race of the day was enough to give the Australians 25 points and a two-point lead over the British team.

The organizers pulled the plug on the fourth and final fleet race due to unfavourable conditions and a lack of wind.

But Slingsby and Australia were able to navigate the course better than their rivals and head into Sunday with a narrow advantage.

"Results wise, it went as well as it could have," Slingsby, the team's driver, told The Athletic. "We have still got a lot to learn and I made some mistakes in the start, especially in one of them we sort of broke the starboard, which was like an own goal with no other boats around.

"In races one and three, we probably overtook seven or eight boats and that's very tough to do on such a small course. We just managed to occasionally stay on the foils a bit longer than others and and a couple of times we managed to get around the mark scot-free and other boats piled up."

The British team followed up their victory in Saint-Tropez, France, with another solid day on the water and are in a good position ahead of the final two fleet races and the winner-takes-all final.

As a result of the relatively poor sailing conditions, only three athletes were on board as opposed to the usual six and the wingsails was set to the all-purpose height of 24 metres.

"It's not too bad (with only three on board), but what really adds that extra element is trying to race," Dylan Fletcher, the British team's driver, told The Athletic. "Normally, I'm looking around a lot and I've got my head out, but now I'm having to focus on sailing the boat a lot more.

"When you are having to do three jobs, making the tactical decisions whilst also trying to sail the boat fast is where it becomes challenging."

Switzerland, at their home event, ended the day in third, but it was another day to forget for the American team.

They were disqualified from the first race after nearly causing a collision with Denmark, although they followed that up with a fourth-placed finish in the second fleet race, only to then finish 12th in the third race.

"It's super frustrating," America's Taylor Canfield told The Athletic. "I'm frustrated with myself. We walked through the situation coming into the day over and over again about what do we do if we're early at the start and about to be shut out, and the answer is go over the line early, don't get overlapped with another boat.

"Sure enough, we found ourselves in that situation and we pulled the trigger late and we got overlapped and that's the worst thing that can happen."

Due to a storm threat, Sunday's racing has been brought forward by 90 minutes, meaning it will now begin from 1pm BST (8am ET).

Switzerland SailGP: Australia on top, USA disqualified in race one, two races canceled