Top seed Jannik Sinner reached the quarter-finals at the Halle ATP grass event in Germany on Thursday but only after a big battle with Hungary's Fabian Marozsan.
The Italian won 6-4, 6-7 (4-7), 6-3. He pulled away in the decider, taking a 5-1 lead before losing serve and then recovering.
The Australian Open champion and world number one will face Jan-Lennard Struff on Friday after the German surprised Greek Stefanos Tsitsipas.
The 34-year-old won 6-4, 6-4 having converted his first match point.
In another minor shock, Italy's Matteo Berrettini was beaten in three sets by American Marco Giron.
Hubert Hurkacz also made it through to the quarter-finals. The Pole, who won the German grass court tournament in 2022, beat Australian qualifier James Duckworth 7-6 (7-3), 6-4. Hurkacz served 17 aces in the process.
German number one Alexander Zverev is already in the quarter-finals after beating Italy's Lorenzo Sonego on Wednesday.
