Juan Martin del Potro's long-awaited return to clay-court action was delayed by rain at the BMW Open on Tuesday.

The former world number four has been troubled by a wrist injury in recent years, but made his comeback in February and was due to be in action in Munich on day two of the tournament.

However, the 2009 US Open winner was made to wait for his first appearance on the red surface since the 2013 Rome Masters due to the weather.

Wildcard entry del Potro is now scheduled to face Dustin Brown on Wednesday.

Florian Mayer was able to get through his first-round match against fellow German qualifier Matthias Bachinger 6-4 6-4.

Kazakhstan's Mikhail Kukushkin moved into the second round after Evgeny Donskoy retired due to a hip injury when the Russian was trailing 6-2 3-0.