There was no stopping Michael Phelps this time. The same goes for Federica Pellegrini.
Having failed to win his opening two events at the world championships, Phelps finally got gold in the 200-meter butterfly on Wednesday. In the next event, Italy's Pellegrini won the 200 freestyle to become the first woman to sweep the 200 and 400 at consecutive worlds.
Australian great Ian Thorpe, who recorded the 200-400 double in 2001 and 2003, is the only other swimmer to achieve the feat.
"You've just got to always believe in yourself. It's great to be a part of history,'' said Pellegrini, who is also the Olympic champion in the 200. "This was my race, and nobody was going to enter my house.''
China's Sun Yang thrilled the local crowd at the Oriental Sports Center by winning the grueling 800 meters - a non-Olympic event. Ryan Cochrane of Canada took silver, and Gergo Kis of Hungary got bronze.
Phelps let his lead slip on the final turn but then overtook Japan's Takeshi Matsuda early in the last lap to clock 1 minute, 53.34 seconds. He hardly celebrated his win. Matsuda took the silver in 1:54.01, and Wu Peng of China got the bronze in 1:54.67.
Phelps led off the 4-x-100 relay when the United States took bronze on the opening night of the competition Sunday, then settled for silver behind teammate Ryan Lochte in the 200 free on Tuesday.
Already a 14-time Olympic champion, Phelps now has a record 23 golds at worlds
"I wanted to do what I usually do when I'm in better shape,'' Phelps said. "I wanted to step on it from the get-go. I saw the other swimmers at the 150 and I put my hips into it. I know there's a lot more I can do in that race.''
Phelps had a streak of 60 consecutive wins in this event covering nearly nine years until he lost consecutive races to Wu at two minor meets in the United States earlier this year.
Pellegrini has also had a trying two years, following the death of coach Alberto Castagnetti after the 2009 worlds in Rome.
Still, she dominated the 400 Sunday with a second-half burst of speed. This time, Pellegrini methodically reeled in her rivals, moving steadily up from seventh after 50 meters to fifth at the halfway mark and third heading into the final lap to touch in 1:55.58.
Kylie Palmer of Australia won the silver in 1:56.04. Camille Muffat of France took the bronze in 1:56.10.
Pellegrini celebrated by propping herself up on a lane rope, then raised her arms and stuck out her tongue before revealing a wide smile.
One more final was scheduled for later Wednesday, with Cameron van der Burgh of South Africa attempting to defend his title in the men's 50 breaststroke. Phelps was due back in the water for the 200 individual medley semifinals.
Midway through the eight-day meet, no world records have been set - a sharp contrast from the 43 marks that fell at the last worlds in Rome two years ago, before high-tech bodysuits were banned.
James Magnussen, who led off Australia's victorious 400 free relay four days earlier, led the 100 free semifinals in 47.90. American sprinter Nathan Adrian qualified second, and William Meynard of France was third.
Defending champion Cesar Cielo, freshly cleared of doping by the Court of Arbitration for Sport, qualified fifth in 48.34.
Competing in his first world meet, the 20-year-old Magnussen created a buzz with his sizzling opening split of 47.49 against Phelps in the relay.
"I haven't gotten a lot of sleep over the last two days,'' he said. "My mind's just been ticking over, so to get that one out of the way and get another sub-48 is a big confidence booster going into tomorrow night.''
