The Rio de Janeiro Olympics were where Quah Zheng Wen produced proof of his potential, reaching two semi-finals - but it was also where the swimmer thought he fell short.

Hampered by jitters in the 200m butterfly semi-final, he clocked 1min 56.11sec. It was 0.1sec slower than his time in the heats, which would have secured him a berth in the final.

It is a big reason why Quah, 20, is today heading to the United States, where he will swim and study at the University of California, Berkeley.

There, he aims to race regularly in the National Collegiate Athletic Association (NCAA) swimming championships.

"I know I could've been in the (Olympic) final for sure. I was slower at night than in the morning and I wasn't trying too hard in the morning," said the swimmer, whose national service is deferred till after the 2020 Tokyo Olympics.

"It (goes) back strongly to my decision to go (to the States). One of the huge benefits of collegiate swimming is the amount of racing they do in a tired state. Just being able to get up and race when needed is a huge skill to have and will definitely help on a bigger stage in the end."

The 10-time SEA Games gold medallist still needs approval from the NCAA to participate in the swimming championships, which begin in March, but Quah said he is confident the decision will be positive.

There are questions over his amateur status given that he is a brand ambassador for Liberty Insurance.

NCAA rules forbid athletes from accepting financial assistance based on athletic skills or participation.

At Berkeley, he will train in a team who were runners-up in last year's NCAA Swimming and Diving Championships Division 1, the competition's top tier.

Before settling on the team nicknamed the Cal Bears, Quah had visited several universities, including the prestigious Stanford University, and Auburn University, where he would have been reunited with former national coach Sergio Lopez.

Explaining his choice, Quah said: "One big reason was the vibe of the team - I wanted to be part of a team that was really dynamic and quick. The team's intensity, it sounded pretty amazing and drew me in.

"Another thing I liked was that the men and women train separately. This allows the coaches to focus (on fewer swimmers)."

Being with one of NCAA swimming's powerhouses has also emboldened him to aim high.

He said of July's swimming world championships in Hungary: "I'm definitely hoping to be in a final. I'm pretty excited to see where I'm going to be at after a couple of months with them."

Quah, who had secured a place in the Yong Loo Lin School of Medicine at the National University of Singapore (NUS), will be studying biology and chemistry at Berkeley, although he stressed that he still wants to be a doctor.

A bachelor's degree is required to read medicine in the US.

While it was a huge sacrifice to put his post-swimming aspirations on hold, he said: "You just have to take a step back and look at what you want and if it's worth it.

"If you can answer those questions, it makes the decision a whole lot easier.

"I want to thank all who backed me up, especially NUS, which has been really supportive."

Ultimately, the long-term target would be to possibly win a medal at the 2020 Olympics, and Quah is itching to make amends.

He said: "I wish I had made (the 200m fly final in Rio) and that I wasn't so on edge in the semi-final. That can't be helped now.

"But I will be ready in 2020."