Adrian Mannarino succumbed to a surprise Stuttgart Open first-round loss at the hands of James Duckworth on Wednesday.
The seventh-seeded Frenchman, knocked out by Aljaz Bedene in the first round at Roland Garros, was beaten 6-3 6-2 by a player ranked 65 places lower than him, with Duckworth outside the world's top 100.
Home hopes Yannick Hanfmann and Peter Gojowczyk progressed, the latter coming from a set down to beat Ilya Ivashka 5-7 6-4 6-2, but there was no such joy for fellow German Dominik Koepfer after he fell to wildcard Jurij Rodionov.
Elsewhere in the draw, there were wins for Feliciano Lopez, Sam Querrey, Dominic Stephan Stricker and Jordan Thompson.
