With a time of 5:05.5, the 15-year-old, who has only recently moved into long-distance swimming, finished a minute faster than Iran’s Alireza Amirimargavi, who could only record a time of 6:47.58.

Today’s win followed up the gold and silver medal he won in yesterday’s 100m butterfly and 100m backstroke respectively.

After the race, Zhi Wei, who swims in the S13 category told Straits Times: "Swimming the 400m free is new for me as I started out as a sprinter.

“But my coach Roland Tan wanted me to be more versatile, so he's been teaching me things like cardio endurance and how to have a more efficient stroke in the last three months."

"I was fortunate to be in lane one today because I could see where the others were when I popped my head up and this helped me to pace myself, and to start and finish strong."

Zhi Wei added that his long-term goal is to qualify for the Tokyo 2020 Paralympics.

"My coach and I are working on a three-to-four-year timeline and I really hope to qualify for the Tokyo 2020 Paralympics," he said.

"The priority is 100m fly but also the 400m free now. My personal best today has definitely shown me that I can go even faster in the long distances."

Today also saw an incredible performance by Japan’s 16-year-old Sakura Koike, who recorded a time of 1:41.15 to secure bronze in the 16 to 18-year-old event of the girl’s 100m backstroke

Koike competes as an S7 and her excellent time even bettered several higher category athletes, including some S10 swimmers.

17-year-olds Honoka Okabe and Honoka Nakamichi, also of Japan, recorded times of 1:22.07 and 1:25.81 respectively to take the top two positions on the podium in that event.

The competition continues tomorrow.