Mario Mola claimed victory from South Africa's Richard Murray as Britain's Olympic champion Alistair Brownlee came fourth in a hard-fought World Triathlon Series race in London.
Brownlee, after a disappointing fourth place in Japan, led the field into the final kilometre but was outpaced.
"I went hard but with 100m to go I had nothing left," he told BBC Sport.
American Gwen Jorgensen won the women's race to replace Briton Jodie Stimpson, who finished 11th, as series leader.
Fellow American Sarah Groff was second, with Australian Emma Jackson third.
Jorgensen now leads the rankings from Stimpson after four rounds, with another Briton, Helen Jenkins, in fourth.
The men's podium places were completed by Portugal's Joao Pereira, with younger Brownlee brother Jonny fifth, ahead of series leader Javier Gomez.
Alistair Brownlee has said he is prioritising success at this summer's Commonwealth Games, but the 2009 and 2011 world champion was clearly determined to replicate the display that earned him Olympic gold in the same Hyde Park setting in 2012.
After Slovakian Richard Varga led a 1.5km swim, Brownlee repeatedly came to the front of a group of riders seeking to open up a gap over a 40km course on the bike.
Despite catching the leaders from the swim, all the rivals were together coming into the 5km run. It was Alistair who again set the pace but he was soon marked by brother Jonathan, Murray and Spaniards Gomez and Mola.
As the final kilometre approached, Gomez and Jonny Brownlee were dropped by Alistair's aggression, but it was Mola who had the better tactics on the day as he ran home for a first world series victory ahead of Murray in the final sprint.