Nathan Adrian slapped the water with his hand, causing a splash that reached above the head of the first American to win the 100-meter freestyle at the Olympics since Matt Biondi.
Then, Adrian hung on the line rope and buried his face in his hand.
Whew was that close!
"I kinda touched well and (thought), 'Oh, sweet, I've won,'" said Adrian. "Then there's 10 to 15 seconds. Holy crap, this is the Olympics. I've been watching this since I was a kid."
Adrian became the United States' first 100 free champion of either gender since Biondi in 1988 when he out-touched Australian world champion James Magnussen by .01 seconds Wednesday night.
The slimmest of margins.
Adrian was running third after 50 meters but world record holder Cesar Cielo and Canadian Brent Hayden both faded. The U.S. trials champ then held off Magnussen's charge to win in 47.52 seconds. Hayden ended third, .27 seconds behind Magnussen for the bronze.
"I think I got a pretty good touch," said Magnussen. "When you lose by that much you look back and think what could I have done better but I have no regrets. I haven't had a great deal of sleep."
More records fell at the Aquatics Centre, including some set by Americans.
Missy Franklin, Dana Vollmer, Shannon Vreeland and Allison Schmitt gave the U.S. an Olympic record in the women's 800 free relay, winning the final by 1.49 seconds over Australia with France in third.
The Americans finished in 7 minutes, 42.92 seconds to smash the 2008 mark of 7:44.31 set by Australia.
Rebecca Soni, the reigning Olympic champion, set a new world record in the semis of the women's 200 breaststroke with a time of 2 minutes, 20 seconds flat -- .12 ticks off Canadian Annamay Pierse's old 2009 mark.
Meanwhile, Ryan Lochte and Michael Phelps set themselves up for their second head-to-head race of the London Games after both made the final of the men's 200 individual medley.
Lochte, the world record holder, blew away Hungary's Laszlo Cseh by .61 seconds for the fastest time in the semis.
The final is Thursday night.
Phelps is the two-time defending champion at the distance and will be looking to become the first male swimmer to win the same Olympic race three times in a row two days after setting the all-time Olympic medal record. He swam in the first heat with Lochte and was .98 seconds slower.
Lochte, of course, won the 400 IM Saturday in the first medal race here and Phelps was fourth, the first time he finished off an Olympic medal podium since he was 15.
"We love racing against each other," said Phelps. "Neither of us likes to lose. I like to say we bring out the best in each other."
Daniel Gyurta won the men's 200-meter breast with a world record time for Hungary's first swimming medal here.
Gyurta took over on the last two-plus laps and touched in 2 minutes, 7.28 seconds to shave .03 seconds off the previous world mark set by Australian Christian Sprenger in 2009.
He beat Great Britain's Michael Jamieson by .15 seconds. Jamieson won the host country's second swimming medal at these games after getting "so many messages of support" from fans.
"I was desperate to get on the podium to thank everyone," he said.
Japan's Ryo Tateishi won bronze .06 seconds ahead of teammate Kosuke Kitajima, who failed in his latest bid to become the first male swimmer to win the same event in three straight Olympics despite leading after the first 100 meters.
Americans Scott Weltz and Clark Burckle were fifth and sixth.
China's Jiao Liuyang won the women's 200-meter butterfly with a burst after the last touch.
Mireia Belmonte Garcia led after the 100 and 150 marks but Jiao closed with a final split more than two seconds faster than the Spaniard to set an Olympic record with a time of 2 minutes, 4.06 seconds. It shaved .12 seconds off 2008 gold medalist Liu Zige's old mark.
Japan's Natsumi Hoshi won the bronze while Americans Kathleen Hersey and Cammile Adams were fourth and fifth. Hersey missed a medal by .30 seconds. Liu was eighth.
The final of the men's 200 backstroke is about 30 minutes before the 200 IM on Thursday. Lochte also qualified for that race Wednesday night with the second best time in the semis behind U.S. teammate Tyler Clary.
Clary is the U.S. teammate who criticized Phelps' training in a newspaper article weeks before the London Olympics started. A day after Phelps won his 19th Olympic medal to set the all-time record, there wasn't much to be critical of.
"He's won more medals than any Olympian in history," Clary said after morning heats. "That should speak for itself. The guy's an incredible athlete."
Clary said it was "pretty cool" that U.S. President Barack Obama sent Phelps a tweet early Wednesday morning London time. Even cooler: The president called Phelps as he was on his way to the pool for the evening semis, according to a tweet from the swimmer.
Also Wednesday night, Ranomi Kromowidjojo of the Netherlands got a new Olympic record in semis for the women's 100 free with a time of 53.05 seconds.
Franklin qualified third fastest and American teammate Jessica Hardy got the eighth spot in the final by .07 seconds while world record holder Britta Steffen of Germany failed to qualify.