Britain's Tom Daley and Pete Waterfield claimed a dramatic gold in the Diving World Series event in Sheffield.
Daley, 16, and Waterfield, 30, left it late, producing a superb final dive in the 10m synchronised final to pip China's Cao Yuan and Zhang Yanquan.
"It's absolutely incredible, not at any point did we think we were going to win that," Daley told BBC Sport.
It was only the pair's second international competition. US duo David Boudia and Nick McCrory were third.
Daley and Waterfield showed how quickly they are gelling as a team, building on their bronze medal at the last World Series event in Beijing with victory in front of a sell-out home crowd at Ponds Forge.
Their performance bodes well for their chances of glory at the London Olympics in 2012 as the British pair showed great composure in their final two dives to take advantage of slip-ups from their competitors.
They nailed their new four and a half somersault dive in the penultimate round as all of their rivals faltered.
The English duo then snatched the lead for the first time with their final dive, ending with an overall score of 449.43.
"That [the penultimate dive] was our newest dive and it saved us today," said Waterfield.
"The two dives that we normally drill we didn't land today as good as normal, but that four and a half saved us. We are glad we are using it.
"This is our second international competition together so we didn't expect anything.
"We wanted to come here and put in a good performance and if we got a medal it was a bonus. To get a gold medal is amazing."
Daley admitted this week the synchro was his best shot at a medal at next year's Olympics, despite the 16-year-old being world champion in the individual platform.
He said Friday's victory would be a significant boost to the English pair's confidence, especially as Chinese divers had won all but one of the 17 gold medals on offer at World Series events so far this year.
"The Chinese don't lose, especially with those two young Chinese divers who when you come up against them most people say silver is gold," Daley said.
"We just went out there and did our best; if you put the Chinese under pressure they don't like it.
"It normally takes years to get the right timing on the board and we are very lucky to naturally have that timing. We just need to now work harder and harder because we have lots more to get out of the list.
"Like Pete said we missed our first two dives, so we can do a lot better. But, honestly it does feel amazing, especially to do it in front of a home crowd."
In the women's 3m synchro Rebecca Gallantree and 14-year-old partner Alicia Blagg proved they are able to compete with the best after finishing fifth.
While they never truly threatened the medals they finished less than nine points behind third place, with China's He Zi and Wu Minxia maintaining their perfect record at this year's World Series to win gold.
Earlier, junior world champion Jack Laugher underlined his growing reputation by posting an international personal best in the 3m springboard.
Laugher overcame cramp in his right leg mid-way through the competition to score 436.90 and continue his improvement in his first year in senior ranks.
The competition was eventually won by China's Qin Kai who again beat his countryman and Olympic and world champion Chong He, while Hu Yadan won the women's 10m platform in the night's final event.
Fina Diving World Series
Saturday 16 April (1345-1730) (view on Freeview 1630-1730)
Men 3m Synchro
Women 10m Synchro
Men 10m - Daley