Nadal was also 16 when he played the event in the Spanish capital for the first time, in 2003, four years before Blanch was born.
The youngster admitted it will be daunting to face one of the game's greatest ever players at his home tournament, even if his fellow left-hander Nadal is seemingly close to ending his career.
"I'm really excited, obviously a little bit nervous," said Blanch.
"But I'm just really happy to be playing against Rafa. I'm ready to go out and just enjoy every moment.
"I know there's going to be a lot of people and they're going to be against me."
Despite his youth, Blanch has already lived in four different countries and can speak English, Spanish, Chinese and Thai.
"I was born in Boca, but when I was one week old, I moved to Thailand for my dad's work," Blanch told atptour.com.
"So I trained there until I was eight years old, with a tennis court in my backyard. I would practice there with my brothers.
"We brought a coach from Argentina, and then eventually I moved to Argentina.
"I trained there for four years, and then I went to the USTA (in Orlando), and then eventually now to Ferrero (Tennis Academy in Alicante, Spain). So, it's been a wild journey."
Blanch made his ATP debut at the Miami Open last month, losing to Czech Tomas Machac.
"Obviously, Miami helped me (get used to the big stage) a bit, but it's always been a thing that I've liked playing with a crowd and I've always enjoyed that," he said.
He has been practising with Carlos Alcaraz in Alicante and impressed the two-time Grand Slam champion, who faced Nadal on his 18th birthday at the Caja Magica in 2021.
"I've practised with him a few times in the academy," said world number three Alcaraz.
"I know that he has good tennis. He plays very well for his age. I told him just to enjoy the moment (against Nadal).
"This moment is going to be really helpful to his career. It was really important to mine, when I faced (Nadal) in 2021 for the first time. I learned a lot from that match and living that experience was really helpful."
