PHOENIX (Reuters) - No-one was more excited to see Michael Phelps back in the pool than his greatest rival Ryan Lochte.
On dry land, the pair are good friends and have been on the same teams at Olympics and world championships, but in the water, they are the fiercest of competitors.
It's a friendly rivalry that has benefitted both men, forcing them to push themselves to new limits in a bid to outdo each other.
Like Jack Nicklaus and Arnold Palmer or Roger Federer and Rafa Nadal, they share a deep and mutual respect but neither likes to lose.
"Racing against Michael is probably the hardest thing to do and I love it," Lochte said.
"l've been racing against him since 2004 and I know that every time I go on those blocks and he's right next to me, it's going to be one of the hardest races.
"I know he's going to push me to the limit and my body to places it doesn't want to go, and I love that."
Like everyone else, Lochte was in awe of what Phelps did in Beijing when he won an unprecedented eight gold medals but rather than concede defeat, he used it to motivate himself.
Instead of ducking Phelps, he decided to take him on. He gave up junk food and devoted himself to a brutal training routine which paid off when he beat Phelps in two head-to-head races at the 2011 world championships.
At the 2012 London Olympics, Lochte easily beat Phelps in the final of the 400 meters individual medley but Phelps turned the tables on him in the 200 IM. In the 4x200m freestyle relay, they joined forces, winning gold for the United States.
Although Phelps' total of 18 Olympic gold medals dwarfs Lochte's five, Lochte is the only swimmer to have enjoyed any regular success against the sport's most decorated competitor.
"It's a fun, friendly rivalry that we have," Phelps said. "I think we just bring the best out of one another.
"When we get in the water I'm going to do everything I can to try and get my hand on the wall before him in every single race and it's the same for him."
Their mutual admiration was evident this week when Phelps made his comeback to competitive swimming after retiring following the London Olympics.
It was just a relatively low-key meet in suburban Phoenix, but as fate would have it, they lined up against other in the final of the 100 meters butterfly, an event in which Phelps holds the world record and has won at the past three Olympics.
On the surface, there was little at stake and the pair engaged in a little slapstick comedy, chatting and joking with each other.
Phelps had not raced for nearly two years and Lochte is making his own comeback after knee surgery last year but like two heavyweight boxers, the smiles disappeared and they started slugging it out as soon as the starter's gun was fired.
Although Phelps was the undisputed king of butterfly before he retired, Lochte beat him this time, getting his hands on the wall first after a ding-dong battle that had the crowd on their feet. Phelps congratulated Lochte and Lochte patted Phelps on the shoulder.
"I'm so glad he's back." Lochte said. "Me and him, we've got history.
"When he left swimming, it kind of broke my heart a little because I love getting the blocks and racing him.
"Racing him against him is so much fun, it's a challenge and now that he's back, I've got a big old smile."
By his own admission, Lochte struggled for motivation after Phelps quit. He did won three gold medals at the 2013 world championships in Barcelona but was losing interest and when he injured his knee late last year, he thought about retiring himself.
"I was going through a rough patch right after the worlds, I wasn't really motivated about getting back in the water then my injury with my knee happened and I was like ‘you know what, maybe I should just thrown in the towel now'," he said.
"But I didn't. I found that little spark that kept me going, I found different ways of making swimming fun again and having Phelps back in the water definitely helps because we're going to be back pushing each other.
"I wasn't having fun, I wanted to quit, I wanted to hang up the Speedos but with the help of my coach and my family and all my fans pulling for me, I got back into it."
Unlike Phelps, who is reluctant to talk about how long he will stay in the sport in his return, Lochte has made it clear he wants to go to the 2016 Rio Olympics, although he is unsure which events he will race in.
And the 29-year-old, who is year older than Phelps, is convinced his friend and great rival will be right there with him and be as formidable as ever.
"One thing about being a racer and being in the Olympics and swimming all those events, one thing you don't lose is the racing ability, that competitive edge," Lochte said.
"He could have taken 10 years off and come back but he would never lose that ability get his hand on the wall.
"He's a racer and that instinct will be with him until the day he dies. There's no doubt in my mind that when he came back it was going to be a battle because in any race he swims, he's going to make the other swimmers hurt because that's what he does best, he's a racer."
Editing by Gene Cherry