The Hong Kong player, who is ranked 67th among world juniors, won a three-set thriller against China's Shi Yuqi - 21-12, 16-21, 21-19 - in a semi-final that lasted 62 minutes the day before. And in the final he had to face another mainland player, world junior number 191, Guipu, who won in straight sets to claim the gold medal.
China's senior team head coach Li Yongbo was there to watch the battle between the two rising stars. Ronnie Wong Man-chiu, the Hong Kong delegation chief, was also in the stadium to support the city's player.
In the final, Cheuk-yiu took advantage in the first game with his astonishing overhead jump smashes. The angle of his smashes was sharp and the shuttlecock landed so quickly that Guipu could hardly return the shots.
Cheuk-yiu reached game point first at 20-18 but could not convert those chances and was taken to deuce. He then had his third game point at 22-21, but missed out when he misjudged a shot by his rival. He thought it was going out, but it landed on the baseline.
Guipu won the first game 24-22. In the second game, both players played patiently.
At the interval, Guipu was only leading 11-10. Unfortunately, a drop in stamina caused Cheuk-yiu's defeat not long after the break, as Guipu took the second game 21-14. The gold medal battle lasted 48 minutes and Guipu won the best-of-three-games match 2-0.
Despite the defeat, many were impressed by Cheuk-yiu's performance. The official news service of the Games billed the final as the "Lin Dan vs Lee Chong Wei" of the junior badminton world, comparing the two young players to China's Olympic champion and Malaysia's world number one, respectively. This showed how intense the match was.
An exhausted Cheuk-yiu told Young Post that he gave everything in the final.
"Yesterday's one-hour match was so tiring. Before today's match, I hadn't fully recovered from that battle. My game plan for today was to win the first game, then use the second game to rest and recover and wait for opportunities in the decider," he said.
"I knew that my chances of winning were slimmer after dropping the first game. But I told myself to keep going, stay patient and fight for as long as I can. So I gave my best and I am really happy to win the silver medal in the end."
Guipu also praised Cheuk-yiu's skills. "My rival has a uniquely fierce style of attack and he played so well today, especially in the first game. I think he is an outstanding player," he said.
Other Hong Kong badminton players had early exits in Nanjing. Yoyo Ng Tsz-yau lost to Malaysia's Kisona Selvaduray in the first round. The Hong Kong girl was seeded fourth with partner Yonny Chung in the doubles, but was upset by Cheam June Wei and Ho Yen Mei of Malaysia in the second round.