World Aquatics Championships: Lois Toulson and Matty Lee win diving silver
Great Britain's Lois Toulson and Matty Lee won silver in diving's mixed 10m synchronised event at the World Aquatics Championships in Budapest.
The teenagers, who won European gold together last month, scored 323.28 to hold off the challenge of North Korea (318.12) in third, with China claiming gold (352.98).
Tim Shuttleworth won bronze for GB in the 5km marathon swimming event, but Olympic champions Jack Laugher and Chris Mears were only fourth in the synchronised 3m springboard.
'We suit each other'
Toulson and Lee were competing in their first global competition as a pair.
"We're over the moon," Toulson, 17, told BBC Sport.
"It was quite a long competition but we stayed calm and delivered when it mattered. I still think I could make improvements, but obviously we're happy."
Lee, 19, added: "It's really difficult when you're a boy and girl pairing but we seem to suit each other really well and I feel like I'm relaxed diving with Lois so it's certainly a good partnership."
Rio Olympian Toulson will next compete in the women's synchronised 10m platform event - alongside 28-year-old Tonia Couch - on Sunday.
Lee, a European Games gold medallist in 2015, will feature in the men's individual 10m platform event on Saturday, 22 July.
'Finishing fourth sucks'
Later, Laugher and Mears were second after four of their six rounds, but two poor routines cost them a podium place.
Russia claimed a surprise gold ahead of China, with Ukraine third.
Laugher and Mears were looking to complete the set of major diving titles to add to their Olympic, European and Commonwealth successes.
"Finishing fourth sucks," Laugher, 22, told BBC Sport. "We are disappointed."
Mears, whose training time has been limited this year because of a long-standing back problem, denied pressure had impacted on the duo's performance.
This was their first major event since they became Britain's first Olympic diving champions, at Rio 2016.
"We didn't feel that stress and we block out what's happened before," Mears, 24, told BBC Sport.
"Preparations weren't perfect and you always have niggles but today is a bit of heartache because we really wanted to medal at this event."
Laugher will return for the individual 3m springboard event, which begins on Wednesday.
Shuttleworth pleased with bronze
Shuttleworth, meanwhile, described winning a bronze medal as "amazing".
The 20-year-old finished in a time of 54 minutes 42.10 seconds at Lake Balaton in Budapest.
Frenchman and Rio 2016 bronze medallist Marc-Antoine Olivier won gold (54:31.40), with Italy's Mario Sanzullo in second (54:32.10).
The Championships are taking place in Hungary between 14 and 30 July.
The BBC will have live coverage of the swimming competition on television, online, mobile, app and Connected TV between 23 and 30 July.
Analysis - 'Lee and Toulson mightily impressive'
Diving and swimming commentator Bob Ballard:
"It feels quite gratifying to have marked your card on the emergence of Lois Toulson in my diving preview.
"The 17-year-old from the Leeds club, partnering team-mate Matty Lee, has proved she is a big-time operator. It was nerve-wracking for the pair to go last in the dive order in Budapest, but the way they held their nerve with a back two and a half somersaults with one and a half twists to register 79.68 and secure second place in the final, was mightily impressive.
"The European champions are a pairing to get very excited about with the Tokyo Olympics in mind.
"After the 2017 Jack and Chris have been through, losing their coach to the Australian programme, coupled with niggly injuries that have hampered training and competition, it's not a huge surprise that the Olympic champions finished off the podium in Budapest - but that disappointment will make them even more determined going forward. It's a blip and no more.
"I fully expect this disappointment to be a catalyst for Laugher in the individual event next week."