Joan Bosch never needed a crystal ball to see Alex Eala’s potential.

Long before the Filipina star cracked the Top 20, captured her first Women’s Tennis Association title and emerged as one of the hottest names in women’s tennis, Bosch already knew she had something special.

What surprised him was how quickly it all happened.

As Eala prepares for the main draw of the US Open starting 30 August at the USTA Billie Jean King National Tennis Center in New York, the 21-year-old now finds herself on the cups of another milestone.

“I remember that I saw her one day and I was talking to one of her coaches. Alex was, I think, 14 or 15, and I said, ‘For sure, this girl, it’s impossible not to be Top 100,’” Bosch said in an interview on Diary of a Professional Tennis Coach.

“For me, Alex is already good. But the question is how good she can be. No one knows.”

Bosch is no ordinary coach.

Apart from his work at the Rafael Nadal Academy in Spain, the 51-year-old mentor is also a national tennis instructor of the Royal Spanish Tennis Federation, one of the oldest national tennis federations in the world.

He also worked with former world No. 1 Carlos Moyá, including during the Spaniard’s triumph in the 2002 Cincinnati Open and the 2004 Davis Cup.

Now, Bosch has found himself on the sidelines of another player making her own climb through the sport.

From Eala’s breakthrough run at the Miami Open to her historic Washington Open triumph, Bosch has been present through some of the biggest milestones of her young career.

But for the Spanish mentor, Eala’s rise was never simply about ranking points, thunderous forehands or victories over some of the biggest names on the tour.

Bosch, who became more directly involved with Eala toward the end of 2024 before taking on a greater role in her development in 2025, said the foundation of her success was already evident in her approach.

“She’s responsible, super professional. Every morning with the warm-up, this I remember,” Bosch said.

“My plan or my idea is that she could improve everything. You can do many, many things better — from serve, from return, from forehand, from backhand, from volley, from footwork, from endurance, from speed.”

“But it’s true that all these things are a progression, a process.”

Eala is now within striking distance of the world’s elite and is poised to continue her climb after reaching the Top 20 for the first time following her breakthrough North American swing.

But Bosch insisted that chasing a specific ranking is not at the heart of their long-term plan.

Instead, the focus is on making sure Eala continues to evolve.

“I am sure if she plays well she can go a bit more and then you see when she was 50, I felt she was far from the 20s. Now she is 20, you see the Top 10 a lot closer. But it’s not a goal,” Bosch said.

“The goal is always to be better than the year before, and if you do that, most probably your ranking will be almost the same or better.”

Eala has already come a long way from the 14-year-old girl he believed was destined for the Top 100.

Just how much further she can go, however, remains the exciting question.