GSTAAD, Switzerland (AP) -- Viktor Troicki returned from a one-year ban for a doping rules violation with victory in the Swiss Open first round on Monday.
Now ranked No. 847, the 28-year-old Serbian beat eighth-seeded Dominic Thiem of Austria 7-6 (4), 6-4.
Troicki was ranked No. 53 last July when the International Tennis Federation imposed an 18-month ban. He had refused to give a blood sample after losing at the Monte Carlo Masters in April 2013.
The Court of Arbitration for Sport reduced the ban when ruling that Troicki's fault ''was not significant.'' He had argued he felt ill and was scared of needles.
Troicki got a wild card entry from organizers of the clay court event in the Swiss ski resort.
In the Round of 16, Troicki will face Andrey Golubev of Kazakhstan who rallied to beat qualifier Inigo Cervantes of Spain 3-6, 6-3, 7-6 (4).
Fifth-seeded Federico Delbonis of Argentina beat Dustin Brown of Germany 6-3, 6-3.
Juan Monaco was another Argentine to win, 6-4, 7-5 against Victor Hanescu of Romania, the 2008 champion at Gstaad.
The final match on court at Roy Emerson Arena was suspended due to rain when Daniel Gimeno-Traver led 5-4 against wild card Yann Marti of Switzerland.