Philipp Kohlschreiber opened his season with a 7-6 (5), 6-1 victory over Croatia's Ivan Dodig in the first round of the Qatar Open on Monday.
The third-seeded German was joined in the second round by sixth-seeded Viktor Troicki of Serbia, who battled past Bjorn Phau of Germany 6-3, 3-6, 6-4.
The injury plagued Nikolay Davydenko, whose ranking has fallen to No. 48 from a high of No. 3, cruised past Victor Hanescu of Romania 6-2, 6-3.
Top-seeded David Ferrer and second-seeded Richard Gasquet of France play their opening-round matches Tuesday.
The $1.05 million tournament is missing many of the game's biggest stars with Ferrer and Gasquet as the only top-10 players taking part in the event.