Caeleb Dressel won the men's 100m freestyle final at the world championships on Thursday to bag his third title in Budapest and give the United States the gold and silver.
Dressel touched the wall first at 47.17 seconds with compatriot Nathan Adrian, the 2012 Olympic champion, second at 0.70 back as France's Mehdy Metella earned bronze at 0.72.
"Right now, it's all smiles," said Dressel. "I'll let it sink in a bit, it's my first and last event tonight, so I'm excited.
"Man - it's nice to go one-two with Nathan, there's nothing like seeing Americans on top.
"I just want to do my best each time with I go into the water with the flag on my cap."
The 20-year-old completed his hat-trick of world golds by powering home over the final 50 metres in a commanding display having already been part of the victorious 4x100m freestyle and mixed 4x100m medley relay squads.
Dressel also broke a world record in Budapest by swimming the third leg of the mixed medley relay on Wednesday, which lowered the previous mark both in the morning's heats and final.
"I'm on top of the world right now," said Dressel.
"If you had told me this would be my first world title, I would definitely have laughed at you four months ago -- I was over three seconds slower," he added.
Silver-medallist Adrian was pleased to see the USA claim first and second on the podium to silence critics on social media, especially after comptriot Chase Kalisz had earlier won the men's 200m IM gold.
"We're fine with the silver we're stoked to see team USA go one-two," said the 28-year-old Adrian.
"I was starting to see some chirrups on Twitter about Team USA not bringing home the medals, so I was glad to step up and get a medal and watch Caleb and Chase do their thing.
"The 100 freestyle was always going to be close, it's just the nature of that event.
"It's a crazy event, there's a lot going on in the pool.
"If you don't have a good view, you don't even know what's going on, but it's really fun to be part of it."