Americans extend gold tally at short-course worlds updated 2:30 p.m. ISTANBUL (AP) -Matthew Grevers and Olivia Smoliga won men's and women's 100-meter backstroke and Ryan Lochte anchored a relay victory Thursday at the short-course world championships in Istanbul, raising the U.S. team's leading tally of gold medals to six. Grevers won in 49.89 seconds, barely defeating Stanislav Donets of Russia, who finished in 49.91 in the next lane. The American won Olympic gold in the same event. "He is definitely the king of the short course, and I am the king of the long course," Grevers said of Donets. The underwater skills of the Russian are incredible. Luckily, I could catch up with the swimming. Donets said he was "very upset," noting he had posted better times in three races this fall, including at the world cup in Tokyo. Guilherme Guido of Brazil won bronze in 50.50. The 18-year-old Smoliga was swimming in her first major international competition as a senior. She took gold in 56.64 seconds, followed by Mie Nielsen of Denmark in 57.07 and Simona Baumrtova of the Czech Republic in 57.18. Australia's Grace Loh was ahead at the half-way point, but finished fourth. It was awesome. I'm so happy to win a world championships," said Smoliga, who flashed a big smile after the race. She said she had warmed up "differently" and was working on her speed. She also talked to Nielsen before the contest. "She was so nice, it made the ready room relaxing," Smoliga said, who failed to qualify for the London Games. Her nails were painted in the U.S. flag's colors of red, white and blue. In the last race of the night, Lochte established a strong lead for the Americans in the 4x200 freestyle. Teammates Conor Dwyer, Michael Klueh and Matthew McLean maintained control to win gold in 6:51.40. Australia won the silver in 6:52.29 and the Germans were third in 6:53.22. World record-holder Russia ended in fourth place. It was Lochte's third gold medal in Istanbul. He won six gold medals and one silver when Dubai hosted the short-course championships in 2010. He won five medals at the London Olympics, including two golds. Daiya Seto won the 400 individual medley, setting the best time in the heats and then finishing in 3 minutes, 59.15 seconds to win the final. Laszlo Cseh of Hungary came second in 4:00.50 and compatriot David Verraszto took the bronze in 4:02.87. The Japanese swimmer built a lead in the breaststroke leg, his strongest discipline, and held on the rest of the way. World record-holder Lochte did not race in the event. Ruta Meilutyte of Lithuania set a championship record of 29.44 seconds to win gold in the women's 50 breaststroke. Alia Atkinson of Jamaica took silver in 29.67 and Australia's Sarah Katsoulis got the bronze in 29.94. World record-holder Jessica Hardy of the United States was fifth. "I really didn't expect it," said the 15-year-old Meilutyte, who won the 100 breaststroke at the London Olympics. At the moment, it feels just like I have swum a normal race, but it will start sinking in. It's crazy. Meilutyte said the 2016 Olympics in Rio de Janeiro are her next big goal. Fabio Scozzoli won Italy's first gold medal with a 57.10 time in the 100 breaststroke. He was a silver medalist in that event at the 2010 championships in Dubai. "I don't think it is a very fast pool," Scozzoli said. It is not very deep. So I think the times here are not relevant. Anyway, I swam my best time. South Africa's Chad Le Clos finished first in the 100 butterfly, setting a championship record of 48.82. Americans Tom Shields and Lochte took silver and bronze, respectively. Lauren Boyle of New Zealand won the 800 freestyle. The championships end Sunday.