Alexander Zverev on Thursday became the first 17-year-old to reach the quarter-finals of an ATP 500-level tournament since Rafael Nadal in 2004 when he made the Hamburg last-eight.
The former top junior from Germany, who is ranked 285 in the world, defeated experienced 11th seed Santiago Giraldo 6-4 7-6 (8-6) having already beaten Russian fifth seed Mikhail Youzhny in the previous round.
“He’s a tough player and a really tough competitor,” said Zverev. “He got the break when I was serving at 5-4 and I just had to focus and play my game. Luckily, I got through in two sets.”
Nadal was the last 17-year-old to make the last eight of an ATP 500 tournament at Dubai in 2004.
On Friday, Zverev will meet compatriot Tobias Kamke in a bid to become the first 17-year-old to reach the semi-finals or better at a tour-level event since Marin Cilic at Gstaad in 2006.