Germany's Jan-Lennard Struff needed 10 match points to reach the last 16 at the Halle ATP grass tournament on Wednesday.
The 34-year-old beat Italian Luciano Darderi 6-7 (2-7), 7-5, 7-6 (12-10) after two and a half hours. He will now play Greece's Stefanos Tsitsipas on Thursday, who eliminated Henri Squire in the first round on Tuesday.
The German number two had to withdraw from last week's tournament in Stuttgart due to a stomach bug. The after-effects were still clearly noticeable against Darderi.
Struff even had to fend off a match point before eventually prevailing.
German number one Alexander Zverev is among those playing in the last 16 later on Wednesday against Lorenzo Sonego.
