Fifth seed Philipp Kohlschreiber suffered a first-round exit at the Stuttgart Open on Tuesday despite not dropping serve.

Kohlschreiber's clash with Denis Istomin did not feature a single break but it was the Uzbek who had the edge over the German in each tie-break, coming through 7-6 (7-2) 7-6 (7-3).

Only three matches were able to finish on Tuesday in Stuttgart because of inclement weather. Gilles Simon thrashed Matteo Viola 6-0 6-3 and Marton Fucsovics overcame Denis Kudla 6-3 6-4.

Feliciano Lopez won the first set of his match against Viktor Troicki 6-1 before rain stopped play.

Mackenzie McDonald pulled off the result of the day at the Rosmalen Grass Court Championships, the wildcard beating eighth seed Andreas Seppi 6-4 6-2. Fifth seed Stefanos Tsitsipas came from behind to defeat John-Patrick Smith 3-6 6-3 6-4.

Bernard Tomic beat Kevin King in straight sets and fellow Australians Matthew Ebden and Alex Bolt also prevailed over Tim Smyczek and Vasek Pospisil respectively.

There were also wins for Jeremy Chardy, Malek Jaziri and Evgeny Donskoy.