Omaha - Michael Phelps turned the tables on Ryan Lochte in the 200m freestyle final at the US Olympic swimming trials on Wednesday, edging his rival in a thriller as both booked London Games berths.
Phelps, the former world record-holder and reigning Olympic champion, led at every turn with Lochte right on his shoulder.
Both came hard off the final turn, with Lochte turning up the pressure before Phelps's final push gave him the victory in 1:45.70.
Lochte - who beat Phelps in the event at last year's World Championships in Shanghai - was second in 1:45.75.
The two were already booked for an Olympic clash in the 400m individual medley, in which Lochte beat Phelps here on Monday.
Phelps also lost to Lochte in their 200m freestyle semi-final on Tuesday - and said he'd made some changes.
"I saw the semi-finals and watching the turns I just got crushed on the wall so I tried to sort of use more speed and try to take it out," he said.
Lochte was already looking forward to doing it all again in London.
"I love that race," Lochte said. "I love racing against him. "I could be a pool length ahead of him, and he'll still be there at the end. He's a great racer."
Phelps, whose 14 Olympic gold medals include his historic eight-gold haul at Beijing four years ago, returned less than an hour later for the semi-finals of the 200m butterfly, moving safely into the final with the third-quickest time of 1:56.42 behind Bobby Bollier (1:56.06) and Davis Tarwater (1:56.10).
As Phelps was busy lining up more chances to cement his Olympic legacy, teenager Missy Franklin led a changing of the guard in the women's 100m backstroke.
Franklin, the 17-year-old tipped for Olympic stardom after her breakout performance at last year's world championships, surged into the lead on the second lap to win in 58.85 - an American record and the fastest time in the world this year.
Rachel Bootsma, 18, was second in 59.49 to punch her ticket to the Games while 29-year-old Natalie Coughlin, the two-time defending Olympic champion in the event, finished third to miss out on a chance at a three-peat.
Only the top two finishers in each event in the eight-day meeting secure places in the Olympic team.
"I did my best, that's all you can ask for," said Coughlin, who swam under the lane ropes at the end to congratulate the ecstatic teens.
"I have dreamed of this moment, but I never thought it would come true at 17 years old," Franklin told the crowd of 12 000 after she was introduced as an Olympic team member. "Dreams do come true."
Like Phelps, Franklin had a busy night. Her impressive 100m backstroke performance followed an appearance in the 200m freestyle semi-finals in which she advanced to the final with the fifth-fastest time.
Breeja Larson sprung a surprise in the women's 100m breaststroke, winning in 1:05.92 ahead of world champion Rebecca Soni - who secured her London spot in 1:05.99.
World record-holder Jessica Hardy was the odd woman out, finishing third in 1:06.53.
Matt Grevers won the men's 100m backstroke in 52.08 - fastest in the world this year. Nick Thoman claimed the second Olympic berth in 52.86.
Collated results of finals and semi-finals on Wednesday on the third day of the US Olympic swimming trials:
200m freestyle: 1. Michael Phelps 1:45.70, 2. Ryan Lochte 1:45.75, 3. Ricky Berens 1:46.56 4. Conor Dwyer 1:46.64, 5. Matt McLean 1:46.78, 6. Charlie Houchin 1:46.88, 7. Davis Tarwater 1:47.02, 8. Michael Klueh 1:48.29
100m backstroke: 1. Matt Grevers 52.08, 2. Nick Thoman 52.86, 3. David Plummer 52.98, 4. Ben Hesen 53.03, 5. Eugene Godsoe 53.61, 6. Ryan Murphy 53.92, 7. Kyle Owens 54.31, 8. Jack Conger 54.63
100m backstroke: 1. Missy Franklin 58.85, 2. Rachel Bootsma 59.49, 3. Natalie Coughlin 1:00.06, 4. Olivia Smoliga 1:00.46, 5. Bonnie Brandon 1:00.82, 6. Jennifer Connolly 1:00.83, 7. Kylie Stewart 1:00.86, 8. Megan Romano 1:01.02
100m breaststroke: 1. Breeja Larson 1:05.92, 2. Rebecca Soni 1:05.99, 3. Jessica Hardy 1:06.53, 4. Ellyn Baumgardner 1:07.19, 5. Annie Chandler 1:07.28, 6. Emily McClellan 1:07.41, 7. Micah Lawrence 1:07.67, 8. Ashley Wanland 1:07.89
Qualifiers for final: 1. Bobby Bollier 1:56.06, 2. Davis Tarwater 1:56.10, 3. Michael Phelps 1:56.42, 4. Tyler Clary 1:56.56, 5. Mark Dylla 1:57.78, 6. Michael Flach 1:58.04, 7. Dan Madwed 1:58.26, 8. Dakota Hodgson 1:58.45
Qualifiers for final: 1. Allison Schmitt 1:55.59, 2. Shannon Vreeland 1:57.78, 3. Dana Vollmer 1:57.81, 4. Megan Romano 1:57.99, 5. Missy Franklin 1:58.04, 6. Alyssa Anderson 1:58.09, 7. Lauren Perdue 1:58.28, 8. Chelsea Chenault 1:58.64
200m individual medley
Qualifiers for final: 1. Caitlin Leverenz 2:10.51, 2. Elizabeth Pelton 2:11.37, 3. Elizabeth Beisel 2:12.27, 4. Ariana Kukors 2:12.32, 5. Maya Dirado 2:12.62, 6. Jana Mangimelli 2:13.48, 7. Jasmine Tosky 2:13.87, 8. Celina Li 2:14.02