Britain's Keri-Anne Payne booked her place in July's World Championships by winning her first 10km race of the season at the Open Water Cup in Israel.
The Stockport swimmer, 23, led from the front to win in a personal best of one hour, 52 minutes and 12 seconds.
She had already secured a place in the 4x200m relay team for the World Championships in China.
Cassandra Patten finished 10th and also secured her place for China, as did Tom Allen and Dan Fogg in the men's event.
In the men's 10km race in Eilat, Allen was the joint leader going into the final turn but the Swansea swimmer slipped back into the pack and ended up finishing 10th, with Commonwealth bronze medallist Dan Fogg eight places behind him.
Payne's victory continues a fine 2011 after the 2008 Olympic silver medallist broke the British 1,500m freestyle record at the national championships in March.
Mark Perry, British Swimming's open water performance manager, said: "Keri-Anne had an impressive swim throughout the race. It was good to see her go out, attack the race and come out with an impressive victory.
"Tom Allen showed his potential throughout the race and I look forward to seeing what he will do in Shanghai."
Shanghai will be the first step on the way to qualifying for the London 2012 Olympics.
If they finish in the top 10 they will have met the qualification criteria for the Games.
Payne will be in action in the UK next Sunday, taking part in the Great Salford Swim, a 1km mass-participation event that will be televised live on the BBC.