SHANGHAI -- 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.
This was Phelps' fifth world title in the 200 fly -- and nobody else has more than two. He's also won the event at the last two Olympics.
"That's sort of been my bread and butter event," Phelps said. "I didn't want to lose that race again. Having a number of defeats this year is extremely frustrating to me. It feels good to win a race."
Australian great Ian Thorpe, who recorded the 200-400 double in 2001 and 2003, is the only other swimmer besides Pellegrini to achieve the sweep.
"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."
The loudest cheers of the night at the Oriental Sports Center were reserved for local favorite Sun Yang of China, who won the grueling 800 meters -- a non-Olympic event. Ryan Cochrane of Canada took silver and Gergo Kis of Hungary got bronze.
In another non-Olympic race, Brazil's Felipe Silva beat Italy's Fabio Scozzoli in the 50 breaststroke, with defending champion Cameron van der Burgh of South Africa third.
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.
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, hardly celebrating. 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 Tuesday.
A 14-time Olympic champion, Phelps has a record 23 golds at worlds.
"I felt like myself the last 100 of that race. I didn't feel like I was dying," Phelps said.
"I wanted to do what I usually do when I'm in better shape," Phelps added. "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 this year.
Pellegrini has also had a trying two years, following the death of her 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, and 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 her tongue out before revealing a wide smile.
"We saw yesterday that there were a few opponents capable of competing well, but we studied the race and Federica did everything we planned," said the Italian's new coach Frenchman Philippe Lucas.
Lucas previously coached Pellegrini's rival Laure Manaudou, who managed to win the 400 in 2005 and 2007, but won the 200 only once at worlds. She is attempting a comeback from retirement.
James Magnussen, who led off Australia's victorious 400 free relay four days ago, was fastest in 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, 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," Magnussen said.
Phelps also had a semifinal heat, qualifying second behind Lochte in the 200 individual medley, setting up another duel between the Americans for Thursday.
"He's not going to give up and neither am I," Lochte said.