Ryan Lochte and Michael Phelps went stroke for stroke into the wall in the 200-meter freestyle. Lochte's hand got there first, with Phelps touching second.
Imagine what Wednesday night's final will be like.
The world's top two swimmers met up in the same semifinal Tuesday night, with Lochte winning in 1 minute, 46.25 seconds. Phelps was just behind at 1:47.27, setting up another memorable confrontation in the final.
"It's going to be a tough race tomorrow," Phelps said. "It's probably going to be another close one like that."
Phelps will be looking to win for the first time at the U.S. Olympic trials. He got beat by Lochte in the 400 individual medley on Monday, then got edged out again in the semis.
Phelps is the ultimate competitor, hating to lose even the smallest contest. But he knows what's really at stake in Omaha.
"It's about getting spots on the team, that's the only thing," he said. "The most important thing for me is to try and secure a spot, and from here I have 3 to 4 weeks to prepare myself and get some extra training in there. I think it's going to be a lot better than what it is here."
Lochte agreed nothing truly matters until the final.
"We're great racers, we just want to win," he said. "We definitely kicked it in gear the last 50, me and him. We know tomorrow night is going to be a lot faster."
There promises to be plenty of speed in the women's 100 backstroke final.
Seventeen-year-old Missy Franklin was the top qualifier in the semifinals. Her time of 59.06 seconds was less than a second off Gemma Spofforth's world record. Teenagers claimed the next three fastest times, as well: 18-year-old Rachel Bootsma, 17-year-old Olivia Smoliga, and 18-year-old Elizabeth Pelton.
"I love where I'm at right now," said Franklin, the breakout star at last year's world championships and one of the top American hopes for London. "I feel strong, I feel powerful. It's so awesome to feel this way and I'm having a blast. This is what I came here to do."
Natalie Coughlin finds herself in the unexpected role of underdog in her signature event. The two-time defending Olympic champion barely qualified for the final with the seventh-fastest time of 1:00.63. That race came after Coughlin finished seventh in the 100 fly final.
"I was hoping to have a better 100 fly than I did, but you pay for it when you go out too hard like I did," Coughlin said. "After that, I just refocused on the 100 backstroke, knowing all that matters is I get a lane for tomorrow night. We'll see what happens. That's all I can do right now."
Coughlin won't have another event before the 100 back final, like she did Tuesday. She scratched the 200 individual medley, so if she doesn't qualify for London in the backstroke, her only realistic chance left to make the team will be the 100 freestyle.
"Having the morning off to rest and recover and go into that 100 back as fresh as possible will be really important for me," she said.
Olympic champion Rebecca Soni used her patented finishing kick to qualify fastest for the 100 breaststroke final in 1:05.88, more than a second ahead of world-record holder Jessica Hardy, who was second in 1:06.88.
"I always hold on to that last few yards as my strength," Soni said. "I'm always waiting to kick it into gear. I don't want to do it too early, but it felt good coming home, and I'm looking forward to having that same speed closing tomorrow."
Hardy won the 100 breast at trials four years ago only to lose her spot on the Olympic team because of a failed doping test. She served a one-year ban after an arbitration panel agreed with her contention that a tainted nutritional supplement was to blame for her positive test.
She battled anger and depression during the fight to clear her name.
"This is the first time I felt like I can actually have a happy ending," she said. "I can relax and finally have fun and feel grateful."
Matt Grevers is the favorite in the men's 100 backstroke final on Wednesday, going in with the top semifinal time of 53.10. Lochte had the second-quickest time in prelims, but he dropped out of the semis to focus on his next final against Phelps.
Brendan Hansen capped his comeback with a victory in the 100 breast, earning a spot in his third straight Olympics.
He won in 59.68.
Hansen is relishing having another shot at Japanese star Kosuke Kitajima, who swept both breast events at the last two Olympics and is in Omaha for the trials so he could keep up his training under American coach Dave Salo.
"It's cool that he got to see me swim," Hansen said. "Somewhere deep down, he's got to know I'm the only guy to beat him the last 10 years. That might carry some weight."
Hansen retired from the sport after the Beijing Games, having been disappointed in two straight Olympics. He took silver and bronze in the two breast events at Athens and was shut out of an individual medal in China.
"I don't know if my body language has shown it or not, but this is exactly where I want to be," he said.
"In 2008, I didn't really want to be here anymore, I was kind of worn down by the whole idea. Now I'm just having so much fun with it and I feel like I'm running on borrowed time. I'm just really proud of myself for saying that I was going to come back and then actually come back and be back."
Hansen will be joined on the team by Eric Shanteau, who specializes in the 200 breast but claimed the second spot in the 100 in 1:00.15.
Four years ago, Shanteau beat out Hansen for an individual spot on the team shortly after being diagnosed with testicular cancer. He put off treatment until after the games and has been healthy ever since.
"I've been back and forth with that event for so long," Shanteau said. "It's nice having it all come together when it counts the most."
Dana Vollmer, a gold medalist as a teenager in 2004, missed out on the team four years ago while battling injuries and health problems, but will go to London after her win in the 100 butterfly.
Vollmer was more than a half-second under world-record pace at the turn, but she faded on the return lap. But she had built such a commanding lead that she was a full body length ahead when she touched in 56.50.
Claire Donahue claimed the second spot for London in 57.57.
Also claiming a spot on the Olympic team was Allison Schmitt, who got off to a huge lead in the 400 free and held on to win in 4:02.84. Chloe Sutton earned the second spot in 4:04.18.