Ryan Lochte capped a golden day for the United States when he overhauled a flying French 4x200 meters freestyle team to ensure the Americans won their fourth successive title in the event at the world swimming championships on Friday.

The 26-year-old Lochte had earlier romped to victory in the men's 200 meters backstroke title before he anchored the relay team, which also included Michael Phelps, to claim his fourth gold medal of the championships in Shanghai.

"We went out there and did our best. When we hit the 75 (meters) mark, I knew it was over, I knew I had a lot of energy left," Lochte told reporters of his relay leg after he overhauled France's Fabien Gilot to claim gold.

"I was gonna hit the second wall (100 meters mark) and go for it."

Lochte, who had already won the men's 200 freestyle and 200 individual medley golds, pipping Beijing Olympic champion Phelps both times, however said he was disappointed with his time of one minute, 52.96 seconds in winning the 200 backstroke gold.

"I don't think it was good time for me. I know I can go a lot faster," he said.

"I still have a whole year (before the London Olympics), that's something I gotta work on and hopefully I will improve."

BREASTSTROKE DOUBLE

Rebecca Soni added to the Americans burgeoning gold haul when she won the women's 200 breaststroke title, comfortably outclassing the rest of the field to claim the 100-200 breaststroke double in Shanghai.

The U.S. have now won nine gold medals in the pool, and sit just behind China in the overall medal table.

"Overall I am very happy with it. You can't complain too much with a gold medal," Soni said. "It's a nice night for me."

It was not such a nice night for Japan's Kosuke Kitajima, who was swum down by 2009 Rome world champion Daniel Gyurta of Hungary in the final length of the men's 200 breaststroke final.

Kitajima had flirted with the world record throughout the race, consistently turning under the split times set by Australia's Christian Sprenger in Rome in 2009, before he tired up in the last 25 meters and Gyurta overhauled him to win his second successive world title when he touched in 2:08.41.

Kitajima, the double-double Olympic champion, winning both the 100 and 200 gold medals at Athens in 2004 and in Beijing in 2008, had hoped victory would give him a guaranteed ticket to next year's London Olympics.

The Japanese Olympic Committee had said prior to the championships that all of their Shanghai gold medal winners would automatically be selected for the 2012 Games.

The 28-year-old, who had considered retiring after Beijing, finished fourth in the 100 breaststroke on Monday and now will have to qualify for the London Olympics, though he said he was looking forward to the challenge.

"I want to gain back my condition and hopefully I can compete in the Olympics," Kitajima said. "With these young swimmers around, it makes the Olympics even more challenging for me."

The women's 100 meters freestyle also produced the second dead heat of the championships with Denmark's Jeannette Ottesen and Aliaksandra Herasimenia of Belarus both touching in 53.45 seconds -- it was the first dead heat for a gold medal in women's swimming at the world championships since the competitions began in 1973.

French duo Camille Lacourt and Jeremy Stravius dead heated in the men's 100 backstroke final on Tuesday.