It was a simple, 200-metre swim, followed by a customary handshake. But for Singapore's Olympic-bound teenager Joseph Schooling, it was all he could think about the last few days.

Joseph, 16, fulfilled a lifelong dream when he raced alongside American superstar Michael Phelps at last Saturday's 200m butterfly final at the Charlotte Grand Prix in the United States.

Phelps, who has 16 Olympic medals, was in Lane 5. Joseph, who will be making his Olympic debut in London, was in Lane 6.

The result was no surprise.

The 26-year-old Phelps clocked 1min 56.87sec to finish second behind China's Wu Peng (1:56.69). Joseph's time of 2:01.70 placed him last in the eight-man field, 1½ body lengths behind his American idol.

But it was an experience to savour for the Singaporean, who is training and studying in Jacksonville, Florida.

"Swimming beside Michael has always been something I've wanted to do - it's definitely a tick off on my bucket list," he said. "I know that as I get older, I'll become stronger, and I'll fare better beside him."

The two swimmers could not be more different.

Phelps, the king of the Beijing Olympics with eight gold medals, is trying to rediscover his best form ahead of London.

Joseph is simply hoping to emerge from the heats in his pet event, the 200m fly.

He said: "My dream is to qualify for the Olympic semi-finals. If I can make the final eight, I won't really care who I swim beside."

Joseph, widely regarded as Singapore's most promising swimmer, had clocked a personal best of 1:56.67 at last year's SEA Games. That time was better than the last-placed semi-finalist at the Beijing Olympics, where competitors used the now-banned supersuit to achieve faster times.

It was also faster than Wu's winning time last week.

While Joseph is simply hoping to make an impression in London, Phelps is seeking redemption.

The American world-record holder in the 200m fly was outshone by compatriot Ryan Lochte at last year's World Championships, and will be looking to prove that he is still the top dog.

But it is clear who is numero uno in the Singaporean's eyes.

A star-struck Joseph was too shy to talk to his hero during their first meeting in Singapore four years ago, but he managed to get in a few words at the Mecklenburg County Aquatic Center last weekend.

The holder of three national records (50m, 100m, 200m fly) was catching his breath and hanging on to the lane ropes when Phelps extended a hand across.

"My coach told me to go all out in the race, so I was dying, struggling to breathe," said Joseph.

"I was thinking pain, pain, pain... But I knew he usually congratulates his competitors, so I was kind of waiting there too.

"When he reached out his hand, I was telling my hand to 'go go go, just reach out a little bit more'."

Four simple words were exchanged - "Good swim" and "Good job" - between the two swimmers.

But for young Joseph, they will never be forgotten. And he is hoping that in London, he will hear those words from the same man again.