Home favourite Eva Lys reached the last 16 at the grass-court Berlin Tennis Open on Tuesday, hours before returning legend Serena Williams was set to take the court.
At the Steffi Graf Stadium, the Hamburg-based player defeated Polish qualifier Magdalena Frech in straight sets, 7-6 (9-7) 6-3.
Lys is the only German in the main draw of the WTA singles tournament, which has a prize fund of €1.2 million ($1.4 million).
The world number 80, who was given a wildcard, lost her first service game but immediately broke back before squandering several set points at 6-5, forcing a tie-break.
Lys initially let a 5-2 lead slip, but then secured the first set with a bit of luck thanks to a fortunate shot off the net cord.
In the second set, Lys was clearly the better player and won comfortably.
Later on Tuesday, the 44-year-old Williams plays the second match of her stunning comeback to tennis alongside Karolína Muchová. The pair will face Guiliana Olmos from Mexico and the New Zealander Erin Routliffe.
Also in action on Tuesday were a trio of other US stars: Madison Keys, who beat China's Wang Xiyu 7-6 (6-3) 6-1, and US duo Coco Gauff and Jessica Pegula in the doubles.
