-- BUDAPEST, Hungary -- Caeleb Dressel put the United States back on top in swimming's glamour event.
Call it a changing of the guard for the American men.
Dressel, 20, emerged as his country's newest sprinting star with a victory in the 100-meter freestyle, holding off longtime U.S. stalwart Nathan Adrian at the world championships Thursday.
Dressel got off to a blistering start and won in a relative rout in the down-and-back race, touching in 47.17 seconds. Adrian surged from behind over the final strokes to claim the silver in 47.87, edging France's Mehdy Metella -- the fastest qualifier from the semifinals and swimming between the two Americans -- by just two-hundredths of a second.
Dressel climbed up on a lane rope and pounded the water with both fists.
Adrian glided quickly from two lanes over to embrace the new world champion.
"I'm very excited about that," Dressel said. "But more importantly, Americans went 1-2. I think that's more exciting than any time that could be shown on that board."
It was the biggest U.S. triumph in the 100 free since Adrian won gold at the 2012 London Olympics.
Kalisz, meanwhile, extended American rule of the 200-meter individual medley, rallying to claim his first major international championship. The Americans have won the event at eight straight world championships, not to mention at the last four Olympics -- with Phelps or Lochte winning every time.
"The U.S. has always been dominant in IMs, and that's been one of our proudest traditions," Kalisz said. "Michael and Ryan have been the centerpiece of that for almost 15 years now."
But Kalisz is still miffed about a silver medal in the 400 IM at Rio, a setback that ended America's dominance of that event.
"It took a toll on me for a few months," he said. "The second I turned it around into motivation was kind of when I started making leaps forward. I think of that moment every single day. I never forget it. It's probably my biggest motivator."
The American reign of the 200 IM began with Phelps' coming-out at the 2003 worlds in Barcelona.
Lochte had won the last two world titles.
Neither is in Budapest, of course.
Phelps retired for the second time after the Rio Games. Lochte missed out on a chance to qualify for this U.S. team because of a suspension for his embarrassing antics at last summer's Olympics.
Kalisz made sure the Americans didn't miss a beat, finally breaking through on a big stage. In addition to that disappointing silver from the Olympics, he also had a bronze and a silver in the 400 IM at the two previous worlds.
Now, finally, he claimed gold.
It was a huge surprise. Kalisz was only fifth after the opening butterfly lap but stormed back to win in 1 minute, 55.56 seconds. Japan's Kosuke Hagino claimed the silver, with the bronze going to China's Wang Shun.
"If you had told me that this would be my first world title, I would have definitely laughed at you," Kalisz said. "Four months ago, I was over three seconds slower. I know that I was going to be able to go faster than that time, but to get to the level where I am right now ... like I said, I probably would have laughed."
In other events Thursday, Rio champion Mireia Belmonte of Spain stayed on top in the 200 butterfly, finishing strong to deny Katinka Hosszu another gold before the home crowd. Hungary's "Iron Lady" was on top at the midway point, sending the packed house at Duna Arena into a frenzy, but Belmonte blazed past her to win in 2:05.26.
Germany's Franziska Hentke grabbed the silver, leaving Hosszu to settle for bronze.
Also, Brazil's Etiene Medeiros took gold in the women's 50 backstroke, which isn't an Olympic event. The silver went to China's Fu Yuanhui, while Aliaksandra Herasimenia of Belarus earned the bronze.
The final event of the night was the women's 4x200 free relay, in which Katie Ledecky was looking to bounce back from her first international loss. After settling for silver in the 200 free on Wednesday, she was anchoring the U.S. team in the relay final with another shot at her fourth gold medal of these worlds.