They were only fifth to start the laser run at 21sec behind the frontrunners Marlena Jawaid and Daniel Steinbock of Sweden, but led the way with a 12min 29.6sec effort to take the gold at the National University of Public Service.

Mexico's Mariana Arceo and Manuel Padilla started second at 11sec off the pace, and held on to silver with a 12:47.9 laser run.

Seo and Padilla departed the final shoot neck-and-neck, but the Mexican's feet became tangled in a bag to hand his opponent a clear run to the finish line.

Seo admitted "we got a little bit lucky in the laser run and we feel some sympathy for the Mexico team", but said "we are so happy".

Padilla reflected: "I’m a little bit frustrated but the good thing is that we have had three relays this year and in each one we took a medal."

Rebecca Castaudi and Jean-Baptiste Mourcia of France took the bronze with a 12:30.0 laser run, having started in seventh at 34sec adrift of the leaders.

Britain's Olivia Green and Henry Choong led for a time during the laser run, but their time of 12:55.7 meant they had to settle for the fourth place in which they started.

Jawaid and Steinbock fared well in fencing, swimming and riding, but had to settle for eighth after a 13:46.4 laser run.

UIPM President Klaus Schormann described the race as "the strongest field for the mixed relay so far", and praised organisers of the World Cup in the Hungarian capital for a "fantastic week".

Bulgaria's capital Sofia is due to host the last UIPM Pentathlon World Cup from May 9 to 14 before the Final in Turkey's capital Ankara from May 31 to June 4.