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Michael Phelps broke it down for Ryan Lochte before the race.

"I said to him in the meet room, 'This is our last 200 of the meet and our last 200 together,'" Phelps recalled. "We were just joking around, laughing about it. Ryan has probably been one of the toughest competitors ever to swim against."

Racing against Lochte for the last time in what he swears will be his last Olympics, Phelps took it to his teammate, blowing him away in the first three strokes of the 200-meter individual medley Thursday night to win their second head-to-head battle at the London Olympics.

Phelps became the first male swimmer to win the same Olympic race three times in a row, touching in 1 minute, 54.27 seconds to beat Lochte by .63 seconds for his 20th career medal.

Lochte had to swim about a half hour earlier and took bronze in the 200 backstroke to U.S. teammate Tyler Clary.

It was an underwhelming night for Lochte, who was a threat to win two golds in his two races at the Aquatics Centre. After all, he's the world record holder in the 200 IM and was the defending Olympic champion in the 200 back. In fact, Phelps swam the second 100 meters -- the backstroke -- nearly a half-second faster than Lochte to build a big lead. Hungary's Laszlo Cseh was a distant third behind the Americans.

"Whenever I step on the blocks I always want to win, that's the mindset I have. Sometimes you have it, sometimes you don't but overall I'm not too disappointed," Lochte said. "I am coming home to my country with five Olympic medals, so that's something to be proud of."

Phelps got his 20th overall Olympic medal and 16th gold, extending both records. He has medaled in each of his races since finishing fourth in the 400 IM Saturday night, the race Lochte won in their first race against each other here.

"I think we will miss the races because they just showed us an incredible level," said Phelps' coach Bob Boman. "They are two guys obviously very different so it is kind of nice to look at those personality differences."

Minutes after the medal ceremony for the 200 IM, Phelps was back in the pool to qualify with the fastest time in the 100 butterfly, which he has also won in the last two Olympics. The final is Friday night. It's the race Phelps won famously by .01 seconds with a half-stroke at the end over Milorad Cavic at the Beijing Olympics four years ago.

Cavic also qualified. As did Chad le Clos, the 20-year-old South African who idolizes Phelps and beat him in the 200 fly here -- Phelps' signature race. None of the other swimmers are expecting to beat Phelps in his last individual race in his last Olympics.

"He was a bit tired (in the semis) and made a great time so I think tomorrow night will be a little bit unrealistic to try and win," said le Clos.

Americans won the first three golds awarded on Day 6 at the Aquatics Centre. Only Dutchwoman Ranomi Kromowidjojo's win in the women's 100-meter freestyle kept it from being 4-for-4.

American Rebecca Soni was the first swimmer to defend their Olympic title here when she broke her own world record to win the women's 200-meter breaststroke.

Soni broke the world record she set in the semifinals Wednesday night by just .41 seconds, touching the wall in 2:19.59. Japan's Satomi Suzuki was second and Russia's Iuliia Efimova won bronze.

"It still means the world to me that I can be the first one under 2:20," said Soni, who won silver in the 200 breast this week.

Clary, the U.S. teammate who was critical of Phelps' training in a newspaper article, won the 200 back after overtaking the defending Olympic champion Lochte in the last 50 meters.

Clary broke his teammate's Olympic record with a time of 1 minute, 53.41 seconds -- .37 seconds ahead of silver medal winner Ryosuke Irie of Japan while Lochte faded to third, .53 seconds back of Clary.

"I had a pretty good sense that I was behind those guys at the 150 and I knew it was going to take something incredible to get past those two. The fact that I was able to get my hand on the wall first is an unreal feeling. I'm so happy right now," said Clary, who picked up his first Olympic medal.

In semifinals for the men's 50-meter freestyle, world record holder and defending Olympic champion Cesar Cielo of Brazil and American Cullen Jones tied for the fastest time at 21.54 seconds.

American Anthony Ervin, the 2000 Olympic champion who sold his gold medal to aid victims of the Indian Ocean Tsunami and came out of retirement after nine years to give the Olympics another try, qualified third fastest.

Kromowidjojo went up and back in 53 seconds flat to win the 100 free with an Olympic-record time, trimming .05 seconds off the mark she set Wednesday.

She beat Aliaksandra Herasimenia of Belarus by .38 seconds while China's Tang won the bronze.

Missy Franklin, after swimming in semifinals for the 200 back earlier in the night, made up time in the last 50 meters but came in fifth. She was trying to become the first American woman to win the event since 1984 but failed to follow Nathan Adrian, who won the men's 100 free on Wednesday -- the first American of either gender since Matt Biondi in 1988 to capture Olympic gold at the distance.

Meanwhile, Elizabeth Beisel and U.S. teammate Franklin qualified 1-2 for the final of the women's 200 back while Canadian Sinead Russell got the eighth spot.

The U.S. has 23 swimming medals at the London Games, well more than half its total haul so far and more medals in one sport than any country has overall except China.