Swimming superstar Michael Phelps has told BBC Sport he is relishing going head-to-head with fellow American Ryan Lochte at the Olympics.
The pair are due to meet at the US trials which begin in Omaha on Monday, with both aiming to qualify for numerous events in London.
"Being able to watch some of the things he's done and be on the receiving end of some of the defeats he has given me has definitely motivated me, just because I hate to lose," said Phelps.
"One of the cool things about being able to race him, it doesn't matter what shape I'm in, I always leave every ounce of energy in the pool.
"He brings every drop that I have out of my system."
Phelps, 26, won a record eight gold medals in Beijing four years ago, taking his tally to 14 and making him the most successful Olympian ever.
However, Lochte, who has three Olympic golds to his name, is rivalling him for supremacy in London, having won five titles, one more than Phelps, at last year's World Championships.
Phelps says he is looking forward to the challenge of taking on Lochte and told BBC Sport's Matt Slater that he does not like finishing second to anyone.
"I can't stand losing," said Phelps. "It doesn't matter what it is, I always have to be the best.
"I'll practise and do anything, work on some of the small things that make you better. I just despise losing."
Phelps and Lochte are due to face each other in six events at the trials.
Lochte, 27, is entered in 11 events and Phelps seven, although they are unlikely to compete in all of them.
They are scheduled to meet in the 400m individual medley on Monday, then later in the week in the 100m and 200m freestyle, 200m backstroke, 200m individual medley and 100m butterfly.
"He's somebody I enjoy racing against and look forward to racing a lot over this year," added Phelps.
Phelps has admitted he struggled for motivation after Beijing, missing six weeks of practice and being suspended from swimming competitively for three months in 2009 after photographs were published appearing to show him smoking cannabis.
Asked about his performances in the pool, he responded: "2009 were OK, but 2010 was a joke. I mean, it was just horrendous.
"I know it was all because of the decisions that I made. Every choice you make, there comes consequences. I may have made the wrong choice but I was able to learn from it, I was able to grow up from it.
"Getting back into it wasn't that good, wasn't that fun, but I had a lot of motivation. Some of the races I didn't want to remember always popped into my head and fired me up even more.
"It's a good thing I was able to go through what I went through and it's kind of going to help fuel the fire."
The Baltimore-native knows his rivals got closer to him while he was not focused on the pool, but he remains confident heading into London.
"I'm playing catch-up," he said. "While they have been working, I've been sitting around doing nothing. It's not easy but it makes it more interesting and it makes it a little more fun. We're going to get there."
Among the others in action in Nebraska are 17-year-old star Missy Franklin and Olympic veterans Natalie Coughlin are Dara Torres, the latter trying to reach her sixth Olympic Games at the age of 45.