Heather Fell won her second Modern Pentathlon World Cup medal of the year as three Britons finished in the top six in the Czech Republic event.
Fell, 25, went into the final discipline, the 3km run, in fifth place but overtook two athletes, including British team-mate Mhairi Spence.
Spence finished fourth, just ahead of Georgina Harland in sixth.
The result lifts GB hopes ahead of this month's World Championships in Hungary, where Olympic places are up for grabs.
Fell said: "My fencing has been improving and I set personal bests in the swim and the run, so Iím very pleased.
Heather did a really good job and again demonstrated the improvement she has achieved
GB performance boss Jan Bartu
"It makes me slightly more relaxed going to the World Championships," she added. "I know I'm not yet safe for the Olympics, but I think this performance means I'm a bit safer than I was."
Jan Bartu, GB performance director, said: "If athletes are serious about going to the Olympics, they need to be up to this standard.
"Having three in the top six proved that they are. It's a good sign for the British team before the World Championships.
"Heather did a really good job and once again demonstrated the improvement she has achieved in the last couple of years."