In his first appearance in a major tournament, the 19-year-old Holger Rune eliminated the French Open runner-up.
The 40th-ranked Rune beat the fourth-seeded Tsitsipas in Paris on Monday.
The first player to leave the men's brackets was Tsitsipas.
I was very nervous on the court, being frustrated a lot, and I knew I was this way.
Last week was the first time that Rune had won a Grand Slam match.
This is the first Slam tournament with two teenagers in the men's quarterfinals since 1994 and the hard-hitting 19-year-old now joins sixth-seeded Carlos Alcaraz.
The kids are going to want to beat me badly. I want to beat them too. I want to get back at them.
After going up 5-2 in the fourth set, Rune had a bit of trouble closing it out. His lead narrowed to 4-5 after he dropped nine points in a row. He had to save three break points before he could serve up the biggest victory of his career.
The first man from Norway to get to the round of eight at the French Open will be facing Rune.
Marin Cilic is the reigning US Open champion and will be playing a night match with US Open champion Daniil Medvedev.
In his first career Grand Slam quarterfinals, Ruud defeated Hurkacz.
Hurkacz was a semifinalist at Wimbledon last year. He had lost in the first round of the French Open in each of the last three years.
The report was contributed to by the Associated Press.