In a men's singles quarter-final match, Jack fell short against second-seeded Jurence Zosimo Mendoza from the Philippines. Jurence is the reigning champion of the Hong Kong Open Junior Tennis Championships and is ranked 88 in the International Tennis Federation's world junior rankings.
Jack, who is ranked 967, lost 1-6, 2-6. He said he couldn't find a way to tackle Jurence's strong serve. "He is much better than me on court and I didn't have any chance of winning the match," he admitted.
Jack had earlier put up a spirited fight to win a tight second-round match in Nanjing. The Hong Kong teenager went down 1-6 in the first set against fifth-seeded Thai star Teeradon Tortrakul, but fought back valiantly, winning the next two sets 6-4, 6-3.
Playing in high temperatures, Jack showed excellent accuracy with his passing shots and was able to win crucial points in the third set.
"I found myself having a real chance to take the match after winning the second set," said Jack, 14, after beating the more experienced Thai player. "My confidence helped me prevail in the decider."
Jack will show off his on-court prowess again in the ITF U18 Mauritius Open in Mauritius, which kicks off on Sunday. Then another tournament awaits, this time back home in Hong Kong.
"I hope I can get the earliest flight back to Hong Kong to take part in a Grade Five tournament of the ITF Junior Circuit," said Jack, who will officially become a full-time athlete next month.
At the Games, another Hong Kong player, Andrew Li Hei-yin, lost to top-seeded mainlander Zheng Weiqiang 3-6, 5-7, in the second round. Local girls did not fare much better. Eudice Chong and Ng Kwan-yau were both eliminated; Eudice by fourth-seeded Assiya Dair from Kazakhstan and Kwan-yau by second-seeded Sun Ziyue from the mainland. In mixed doubles, Jack and Kwan-yau lost their first-round game, while Andrew and Eudice bowed out in the second round.