Mhairi Spence and Heather Fell dropped out of medal contention as the women's Modern Pentathlon World Cup Final concluded in Greenwich Park.
The British pair began their last event on the fringes of the podium but ended in fifth and seventh respectively.
"I set myself a goal of top six but things could have panned out better," 25-year-old Spence told BBC Sport.
Germany's Lena Schoneborn took gold as Scotland's Freyja Prentice came 12th.
The competition doubled as a 2012 Olympic test event and the temporary venue at Greenwich, which also hosted an equestrian test event earlier in the week, will now be dismantled.
Work to construct the full Olympic venue, which will be considerably larger than for the tests, begins in the early summer of 2012.
Inverness pentathlete Spence fought her way to second place after Sunday morning's fencing and swimming, which took place at the Crystal Palace National Sports Centre.
In 2012, the two disciplines will be held inside the Olympic Park's Handball Arena and Aquatics Centre before athletes transfer to Greenwich.
Neither Spence nor Fell had perfect show jumping rounds but Spence nonetheless began the run-shoot combined event - in which pentathletes have a staggered start based on points earned in the day's other events - well-placed in third, nine seconds ahead of Fell in fourth.
However, Fell struggled to hold her concentration for the shooting element of the finale, while Spence tired in the run.
"That was probably my worst combined event this season," said Devon-based Fell, 28.
"I don't know what I was doing in the shoot, it was terrible. I've got to go back to the drawing board."
Spence added: "Running has never been my stronger event and this course - I don't know who made it but it's my worst nightmare.
"When we walked it the other day it made me want to cry. For someone who struggles with running anyway, it's going to take a lot more out of me."
A blank slate for the women gives Britain's men a rare upper hand in the weekend's results, Nick Woodbridge having become the first British male to win a World Cup Final medal when he took bronze on Saturday.
Britain's female pentathletes have traditionally been much stronger than their male counterparts, winning four Olympic medals at the three Games in which women's pentathlon has featured.
The European Championships in Kent at the end of this month form the next opportunity to qualify places for the Olympic Games.
Britain can send a maximum of two women to the Olympic modern pentathlon next year, but competition to fill those slots is fierce with six names in the frame.
Fell, Spence and Prentice, all ranked inside the world's top 10, are joined by Katy Burke (17th), Samantha Murray (23rd) and Beijing Olympian Katy Livingston (62nd) in the reckoning.
"If it doesn't happen for me then I hope to be still in the squad supporting whoever it's happening for," said Spence.
"I want to push them to achieve whatever is needed to keep our funding for another four years."
The European Championships are followed by September's World Championships in Russia as this year's two key Olympic qualifiers.