KAZAN, Russia (AP) Fighting off windy and choppy conditions, Haley Anderson of the U.S. defended her title in the 5-kilometer open water race to claim the first medal of the FINA world swimming championships Saturday.
She surged to the lead in the closing meters in the brownish waters of the Kazanka River, hitting the touchpad in 58 minutes, 48.4 seconds.
Chad Ho of South Africa defeated Rob Muffels of Germany in a photo finish after they both stopped the clock in 55:17.6. Matteo Furlan of Italy earned bronze in 55:20.0.
''I couldn't ask for a better race,'' Ho said.
China got started on a possible sweep of the diving gold medals with victories in two events.
Si Yajie and Tai Xiaohu led all six rounds in mixed 10-meter, a new event at worlds. They scored 350.88 points in their first high-level meet together.
''I had a feeling like my partner might not be able to complete it, but we made it,'' Si said. ''We probably were not the most synchronized duet since we only had a month to practice.''
Canada's Meaghan Benfeito and Vincent Riendeau were 41.22 points behind in second at 309.66. Domonic Bedggood and Melissa Wu of Australia earned bronze in 308.22.
In women's 3-meter synchro, Shi Tingmao and Wu Minxia won their second straight world title with 351.30 points, with Canada's Jennifer Abel and Pamela Ware were 31.83 points behind for silver. The Chinese led all five rounds in defending their gold from two years ago.
Russia claimed its first gold as a first-time host of the world championships. Svetlana Romashina won the technical routine in solo synchronized swimming, a sport the Russians have dominated for years. It was Romashina's 16th career medal at worlds.
In the 5k, Anderson, the 2012 Olympic 5k silver medalist from Granite Bay, California, used the shorter race as a tuneup for the 10k next week.
''I just wanted to be able to get on the course, feel it out,'' she said. ''My strategy was just to stay toward the front because it's a short race. You got to kind of stay up there if you want to be able to make your move toward the end.''
Anderson's medal was the 500th won by the U.S. in the 16-year history of the world championships.
Kalliopi Araouzou of Greece took silver in 58:49.8, while Finnia Wunram of Germany earned bronze in 58:51.0.
Sharon Van Rouwendaal of the Netherlands led most of the way on the wind-whipped rectangular course, but settled for fourth in 58:55.1 - more than 7 seconds behind Anderson.
The water temperature was 68 degrees (20 Celsius) while the air temperature was 73 degrees (23 Celsius) for the women's race at the course near the Kazan Kremlin, built at the behest of Ivan the Terrible in the 16th century.
''The water wasn't too cold, which was nice,'' Anderson said. ''A little choppy, but it's choppy for everybody, it's cold for everybody. It was nice out there.''
Anderson won the 5k at worlds two years ago in Barcelona, Spain, where the water temperature in the city's harbor was warm, but swimmers criticized the conditions as dirty and smelly.
Numerous boats carefully tracked the field of 41 swimmers, who were strung out after the lead pack. The water is four meters deep on the course - two times deeper than the FINA standard. The bottom of the river in the competition area was cleaned beforehand.
''The quality of the Kazanka water conforms to all the sanitary norms,'' said Dmitry Mikhailov, a deputy director general for sports projects.
The start and finish of the open water events is directly under the 27-meter tower that will be used for the high diving competition next week.
Synchronized swimming joined pool swimming and diving with an event featuring men and women competing together.
In the debut of mixed duet synchro at worlds, the Russian duo of Darina Valitova and Aleksandr Maltsev was first with 88.85 points in the technical preliminary.
Americans Christina Jones and Bill May were second at 86.71, while the Italian duo of Manila Flamini and Giorgio Minisini was third with 84.07. The final is Sunday.
May is back in the sport after retiring 10 years ago. He has been performing in a Cirque du Soleil show in Las Vegas.