His opponent failed to put the ball across the net. A punch of the fist and an unfamiliar cry of Koi (Come on, or Rafael Nadal's Vamos!) followed. Loving the heat, loving the competition, a shy, smiling 13-year-old Ryoto Tachi had won his first title in India, beating Pune's Arjun Kadhe 6-4, 6-2 in the final of the All India Ranking Championship Series, in Mumbai last Saturday.
Miles away from his birthplace in Tokyo, the affable Japanese boy is rising on the Indian tennis charts.
In two weeks, he beat four of India's top-15 players in his age group, having finished runner-up to 15-year-old Advait Kirtane in the under-16 Super Series the week before.
"I am happy to win my first title in India," said Ryoto. "I don't care much about the seedings. Last week (Super series), I came through the qualifiers and reached the final. I don't get nervous while playing; I know if I can play my usual game I can win," he said.
Ryoto started playing the game in Uzbekistan when he was only four. With his father, Yoshisa, working for Mitsubishi Motors, the family has had to shift residence every four-five years. But Ryoto thinks it's only an opportunity to learn different styles of play.
"When I was in Tokyo, they emphasized on strokes. Here my coach (Intikhab Ali) teaches me lots of variations -- how to serve and volley, spins. He wants me to play attacking tennis and hit the ball on the rise.
"Players lob the ball against me a lot because I am short and they think I can't get to it. But I am confident once I get into a rally."
His mother, Masako, who tours with him all round India and Asia, agrees that tennis is his universe at the moment.
"When we told him we would be shifting to India, he was only worried about tennis. He said if he could play the game here it would be okay," she adds.
Though he took some time to adjust, Ryoto loves everything about Mumbai, his home since 2005, right from its perpetual heat to the road-side paani-puris.
"As far as tennis is concerned I like Mumbai best, then Uzbekistan and then Tokyo. I like the weather here; it's always warm. The facilities are also lot better than Japan and there are more courts here.
"And I love the food, not the spicy one, but dosas, and jalebis and paani-puris," says Ryoto with delight.
Ranked as high as 13 on the Asian Tennis Federation list last year, Ryoto's meticulous approach holds promise for a bright future. He enjoys the game, has fun on court and gets along with his competitors, but he is not there to indulge himself.
Before the game, he straps his ankles, knees, hands and places the brace on the elbow.
"For support," he explains. Prevention is better than cure. No missing tournaments because of injury.
Hours after claming his first title in India, he zoomed off to Sri Lanka to play another tournament.
To this young professional, all we can say is Koi!