Gasquet is ranked 38th in the world
Richard Gasquet won his first match after two months on the sidelines following a positive test for cocaine.
The 23-year-old Frenchman beat American Michael Rubin in straight sets but then lost his next qualifying match for the Pilot Pen ATP hardcourt tournament.
Gasquet was beaten 7-6 (7/3) 4-6 6-3 by world number 458 Dusan Vemic of Serbia.
"It's hard to come back, but I'm happy to be playing," said Gasquet, who claimed he picked up traces of cocaine when he kissed a girl in a night club.
Gasquet, ranked 38th in the world, was banned for two-and-a-half months in May after testing positive for cocaine during the Miami Masters in March .
Following his competitive return, Gasquet said he was just focusing on getting his game back in shape ahead of the final Grand Slam of the season, the US Open, which starts in New York on 31 August.
"I just have to play matches and then I will be able to come back," he said. "I am happy playing tennis, with it I have fun, and I am happy to be here.
"My goal is to win one match at the US Open. I have had difficult months, but now it's just to have fun."