Struff was in an enticing match against American tennis player Marcos Giron that ended 7-5, 5-7, 7-6 (10-8).
The competition is in its 44th year and is part of the ATP Tour 250 series for the year 2022 and it will be played from June 6 to June 12.
The final set of the match between Ryabinka and Badosa went to a tie-break which was a back and forth affair for a while before the Spaniard finally took control.
Victoria Azarenka will not play the Stuttgart Open as she will receive her first coronavirus vaccine shots.