Sixth-seeded Thomaz Bellucci was among those to make safe progress to the second round of the BMW Open in Munich on Monday.
The Brazilian made it into the last 16 by beating Russian Mikhail Youzhny, the 2010 champion who lost the first set 6-3, then had to retire at 1-0 down in the second.
Bellucci's opponent in round two will be Ivan Dodig after the Croatian saw off Latvia's Ernests Gulbis 7-6 (7-3) 6-2.
Monday's other first-round action saw Czech Lukas Rosol defeat Denis Istomin of Uzbekistan 6-7 (2-7) 6-4 7-6 (7-2) and Colombia's Santiago Giraldo overcome wild card home favourite Mischa Zverev 7-5 7-6 (7-5).
Source: PA
