He had virtually one hand on the trophy, leading 3-1, 30-15 in the third set of the deciding match at the Schools National B Division Tennis Championships yesterday, when he felt a stab of pain in his legs.
The cramps that hit Caleb Tay in his right calf and left thigh left him sprawled on the court, and cast doubts over Anglo-Chinese School's (Independent) attempts to retain the title.
Officials worked desperately to help him stretch to ease the discomfort. Despite being in pain, Caleb got back on his feet at the Kallang Tennis Centre, to thunderous cheers from supporters.
While he continued limping for the remainder of the match, he managed to beat Raffles Institution's (RI) Jay Tan 4-6, 7-6 (7-1), 6-2.
His victory secured a 3-2 win for ACS(I).
He told The Straits Times: "I just tried to get all the balls back and when I got an easy shot, I just tried to direct the ball away from him - that's how I won the points.
"But during the points where he was attacking me, I couldn't do much because I couldn't move.
"It was thanks to the support from my classmates, coaches and team-mates that I didn't give up and continued fighting."
RETURNING LIKE A CHAMP
I just tried to get all the balls back... It was thanks to the support... that I didn't give up.
CALEB TAY , ACS(I) tennis player on how he managed to win his match despite cramps.
The 14-year-old's gritty performance in the deciding singles match was a gamble that paid off, as ACS(I) coach Ang Hock Chai revealed that Caleb had initially been pencilled in to play doubles.
"Caleb lost his singles match during the semi-finals (against ACS-Barker Road), and we were worried the loss would affect his confidence," said Ang.
"But this morning, we decided we could not base our decision on the one match that he lost, and I think what's nice is not only that he won for his team, but he will also learn how to move on from past losses and remain confident."
ACS(I) clinched their other two points through captain Robin Cheng and Takeshi Koey, who won their respective singles matches.
RI's victories in both doubles matches forced the decider.
In the girls' competition, Raffles Girls' School (RGS) beat Methodist Girls' School (MGS) 5-0 to retain their B Division crown.
RGS coach Gary Tan was happy with his charges' performance, saying that it was a "big step up from the semi-finals".
The 47-year-old named strengthening the doubles pairs and improving net play as a key strategy.
"The girls executed the game plan very well today," he added.
"When you're on court playing a final and facing nerves, pressure and everyone watching, you never know how they will handle it, but I think they took care of business really well."
Ang, who is also MGS' coach, believes the MGS players were affected by their opponents' unexpected line-up yesterday.
He said: "Raffles fielded some singles players in doubles, so I think the MGS girls were shocked and couldn't play their own game.
"Maybe they were over-thinking or trying to avoid hitting to a particular player (in doubles), and when you think so much about your opponent, you destroy your own game."
While he acknowledged that his charges "didn't play to the best of their ability", the 49-year-old is sure they will work harder to go one step further next year.
"Credit must be given to the girls, because it's not easy playing in the finals," he added.
"We will prepare well physically, because when you're physically fit, you'll be stronger mentally. We will definitely work very hard."
Yesterday's finals were the first two of this year's National School Games season.