Britain's Jamie Cooke has won the Modern Pentathlon World Junior Championship in Argentina.
The 20-year-old was way off the pace when he was lying joint 29th after the fencing discipline.
But he produced a trademark powerful swim, an impressive ride and a strong run/shoot to finish the day on top of the podium in Buenos Aires.
"I think this is my biggest achievement yet. I didn't expect to win here, especially after my fence," said Cooke.
"There was a lot of pressure on me in the run/shoot as there were some fantastic runners around me. I also thought I had something to prove after the European Juniors.
"I was second at the World Youths a few years ago and when I realised I had a chance of winning after the second shoot here I told myself there would be no way that I would be coming second."
It takes Britain's medal tally at the championships so far to three after Freyja Prentice's individual bronze in the women's final on Saturday, when the women's team of Prentice, Kate French and Lydia Rosling also won the gold.
Cooke has already achieved the London 2012 qualifying standard, but is not yet certain of place on the team.
He was the only Briton to qualify for the men's final, so GB finished 12th in the team competition.
Britain's last world junior champion was Heather Fell, who took the women's title in Greece in 2003.