Rio 2016 open water champions Ferry Weertman and Sharon Van Rouwendaal delivered a Dutch double in the opening event of this year's International Swimming Federation (FINA) Marathon Swim World Series, held for the first time in Doha.
Weertman took the men's 10 kilometre title in 1 hour 52min 42.60sec, less than a second ahead of France's David Aubry.
The Frenchman clocked 1:52:42.50 to claim silver in the turquoise waters of the Qatari capital's iconic Corniche.
Bronze went to Italy's 2016 and 2017 overall champion Simone Ruffini, who was just a second adrift of the winner as he finished in 1:52:42.70, with France's Axel Reymond touching just 0.30sec behind him.
Weertman remained composed throughout the race, moving to the front in the fourth lap but then dropping back a little to cover new leaders Alex Reymond of France and Italy's David Paltrinieri, the world and Olympic 1,500 metres champion.
The Dutch swimmer then put in an unanswerable sprint at the end of the sixth and final lap to claim gold.
"This is my first win in the World Series - I am very happy about that," said Weertman.
"I felt strong in the fourth lap, so I overtook in the front and immediately I saw Reymond coming.
"He is a very good 25km swimmer so I knew he was going to keep up the pace and I knew I had to stay on his feet.
"I could do that for a very long time.
"I also saw Paltrinieri come next to me and I know he's the fastest man in the 1,500m but I had to stay with him because I know I have a good sprint.
"When I heard that it was in Doha, I thought it would be really hot but it was not.
"It was okay, so the air temperature didn't really matter that much."
Like her male compatriot, Van Rouwendaal was also involved in a tight finish as she took gold in a time of 2:02.24, just 0.80 seconds in front of Germany's Leonie Beck.
Bronze was also closely contested, going to Beck's compatriot Finnia Wunram, who clocked 2:02:26 to finish a tenth of a second in front of Brazil's Ana Marcela Cunha, the 2010, 2012 and 2014 overall champion.
Italy's defending overall champion Arianna Bridi was seventh in 2:02:28, two places ahead of her compatriot Rachele Bruni, the 2015 and 2016 overall champion and Rio 2016 silver medallist, who finished in 2:02:31.
As the women's race moved into its final quarter-of-an-hour the German pair of Beck and Wunman were pushing hard, but Van Rouwendaal produced a powerful finish to take the lead, putting in maximum effort at the last buoy.
"I feel very good," said Van Rouwendaal.
"This is like my best race ever apart from the Olympics.
"I was really relaxed during the race.
"I started behind and at each turn I tried to win a few places and at the end I just kept calm and tried to sprint the last 600m.
"Normally I am in front right from the start but at the World Series I am trying to learn new tactics.
"I can see that this was my best tactic ever."
Beck added: "I did not expect to do so well.
"When the Italians stopped I didn't expect it so I thought 'okay, well I'll just go in front.'"
Doha was the first of nine legs in this season's World Series.
The second stage will be held on May 20 in the Seychelles, which is the second new Tour venue for 2018.