Once a top Spanish amateur player who competed in the national championships, the coach had hundreds of children come under his watchful eye at Manacor Tennis Club on his home island of Mallorca.
“When I hit the ball to Rafael, he went towards it. He didn’t wait for the ball to arrive to him,” Toni tells BBC Sport.
“Normally, when I sent a ball to a small kid, he stood and waited until the ball arrived at him. But my nephew, he went looking for it. For me, this was special.”
That assessment proved to be right. Rafael Nadal was a special talent and, with Toni shaping him as a player and a person, the 35-year-old has gone on to prove it.
No player in history has won more Grand Slam men’s singles titles than Nadal.
The Spaniard equalled Roger Federer’s all-time record of 20 major victories at the 2020 French Open, with Serbia’s Novak Djokovic joining them on the same number after winning Wimbledon.
Yet, as Nadal has so often acknowledged, it is doubtful he would have achieved the same scale of success without the man known throughout the tennis world as ‘Uncle Toni’.
There are many tales of Toni’s tough-love tutelage. Without them, a youngster described by his sister Maribel as “a scaredy-cat” may never have transformed into the ‘raging bull’ we know on court as one of the most ferociously competitive athletes of his generation.
Other than the terracotta courts, you would be hard pressed to find many similarities between Manacor Tennis Club and Roland Garros.
Manacor is a typical Mallorcan village and the tennis club – several clay courts overlooked by a medium-sized clubhouse which houses a restaurant and sun-filled terrace – is similar to many on the Mediterranean island.
Toni, who turns 61 in February, was in his early 30s when Nadal first joined in with a small group of children he was teaching.
In the very early days of their time together on court, when Nadal was still part of the wider group, he would be treated differently by his uncle. But this was no case of nepotism.
The young Rafael – described by Toni as mild-mannered and quiet at that age – used to get annoyed by what he felt was overly tough treatment.
“I demanded a lot from Rafael because I cared a lot,” says Toni.
Nadal’s mother Ana Maria recalls how her young son used to arrive home from training in tears but wouldn’t reveal what was upsetting him.
Once he told her Toni had called him a ‘mummy’s boy’, and she wanted to confront her brother-in-law. Nadal insisted she shouldn’t make a fuss and asked her to keep quiet to avoid “making things worse”.
Nadal has said his uncle used to shout and try to frighten him, sometimes leaving him with a “sinking feeling in his stomach” if he saw it would be just the two of them training together.
If the young boy’s mind drifted off while they were on the court, Toni used to knock balls towards him to grab his attention.
At the end of practice, Toni insisted Nadal had to pick up all the scattered balls and sweep the red dirt, while the other kids wandered off home. If he forgot his water bottle, he had to train without rehydrating in the hot Mallorcan sun.
Toni says all of this, laid bare in his nephew’s 2011 autobiography, is true.
“I believe in the work and I believe in the players who are strong enough to cope with the intensity of this work,” he tells BBC Sport.
“I cannot understand another style of life. In my opinion you always have to know your place in the world.
“This is why I was like this with Rafael. I knew he could cope.”
When an 11-year-old Nadal won the Spanish Under-12s national title, Toni’s sterner side was on show again.
At a small gathering to celebrate the success, Toni dampened the mood by reeling off the names of the past 25 winners. He’d called the Spanish Tennis Federation to obtain them, posing as a journalist.
Nadal had only heard of five; those who had gone on to play professionally. Toni, apparently with a sense of triumph, insisted it highlighted his point: he only had a one in five chance of doing the same.
Another such example came a few years later when Nadal, now 14, buoyantly returned home from an international tournament in South Africa – the furthest he had ever travelled.
He had enjoyed experiencing a different culture, seeing wild animals like elephants and lions for the first time, and he had come back victorious.
In his autobiography, Nadal explains how a homecoming party was organised by one of his godmothers, with a banner featuring a message that was supposed to be “celebrating and deflating at the same time”.
Nadal never got to see it. Toni whipped the banner off the wall, rollicked the godmother, stopped the youngster from going into the party and called him in for training at 9am the next day.
“I wanted him to know that everything he achieved at that age was not very important in terms of the bigger picture,” Toni says.
“I wanted to dampen the expectation. I wanted him to know it was only a little step and if he wanted to progress he had to continue to work very hard.”