Main draw matches kicked off on Monday at the ATP 250 tournament in Stuttgart.
Jiří Lehečka (Czech Republic, 8) def. Benjamin Bonzi 6/4, 6/4
Brandon Nakashima (USA, 6) def. Jacob Fearnley (Great Britain) 4/6, 7/6(4), 6/1
Jan-Lennard Struff (Germany, WC) def. Matteo Arnaldi (Italy) 6/4, 6/4
