The Form Three student from Po Leung Kuk Ma Kam Ming College was among 27 boys who took part in the under-55kg competition in two pools - A and B.
Homer, in Pool A, received a bye in the round of 32. He then had to face a judoka he had never competed against before - Macau's Lio Chon-hou.
Lio had beaten Yemen's Ali Al-Farran to earn the right to take on Homer in the round of 16. Lio beat Ali by an ippon, which is one full point in judo. A competitor who achieves an ippon is declared the winner.
In the match against Homer, Lio was the more active opponent, and he successfully held the Hong Kong boy on the mat. Lio was given a wazari (a half point in judo; two wazari equal one ippon) and a yuko (an advantage) in the first minute.
Unfortunately for Homer, not long after that, the referee overruled the wazari given to Lio and awarded him an ippon instead, thus ending the match and pronouncing Lio the winner.
Homer told Young Post that it was "first-match nervousness" that led to his defeat.
"Facing the huge crowd at Longjiang Gymnasium, I felt enormous pressure," said Homer. "I didn't do what I was supposed to do. The turning point was that I didn't grab Lio's shoulder tight enough, which meant he was able to make a counterattack and score the ippon.
"This was my first appearance in a major tournament, and, after seeing the draw, my goal was only to win at least one match."
Homer's coach, Law Wai-keung, agreed.
"Homer had no problems during his pre-match training in Nanjing," he says.
"It was his mental barriers that cost him the match."
After his defeat, Homer and Law stayed on at the Games to watch the other matches.
"These athletes are all in the same weight category as Homer," says Law. "Homer can learn more about their styles by watching them."
Homer has been training for nine years.