Despite recording the fastest swim at the Modern Pentathlon World Cup Final in Nizhny Novgorod in Russia on Friday, Samantha Murray endured a difficult afternoon to finish 30th overall.
The Olympic silver and World Championship bronze medalist climbed from joint 23rd after the first discipline - fencing - to seventh after being quickest in the pool.
But hopes of a medal faded after dropping to 26th after the ride, and slipping to 30th after the run/shoot.
Samantha said on twitter after the competition: “A solid morning but a bad afternoon.
“No one told me this game would get any easier.”
Britain’s Mhairi Spence - the reigning World champion - came home seventh, having been in the top 10 throughout the day, while the final Brit in action, Katy Burke, finished 32nd.
Spence made the strongest of starts among the Brits. She fenced well, scoring 24 wins from her 35 contests for joint third place.
Murray’s 19 victories put her 19th, while Burke ended her fencing campaign strongly to finish with 15 wins for joint 23rd and 760 points.
Tatsiana Yelizarova of Belarus led the field with 26 wins.
Spence moved to the top of the leaderboard after the swim.
Her 200m freestyle time of 2:13.26 was the 10th quickest.
But it was Murray that went fastest in the pool – her 2:07.23 was the fastest time of the day, adding 1276 points to her total, promoting her to seventh.
Burke also climbed up the field to 18th. Her 2:11.73 was sixth fastest and was worth 1220 points.
Spence maintained her challenge with a solid ride.
She had just two fences down to add 1120 of the maximum 1200 to her total score. That put her second overall.
But Murray didn’t fare so well, taking 812 points as she dropped to 26th place, while Burke dropped to 21st place overall.
It meant Spence went into the run/shoot 10 seconds behind Ukranian Ganna Buriak, with another Ukrainian, Victoria Tereshuk and Brazil’s London 2012 Olympic bronze medallist Yane Marques starting in joint third a second behind her.
Burke started a minute and 26 seconds behind the leader, with Murray a further 19 seconds back.
Tereshuk, Beijing 2008 Olympic bronze medallist and 2011 world champion, won gold, with Russia’s Ekaterina Khuraskina taking silver and Buriak bronze.