Britain's Andy Murray lost in straight sets to Egor Gerasimov in his first ATP Tour match for four months at the South of France Open in Montpellier.
Former world number one Murray, currently ranked 121st, has lost his last four matches on the ATP Tour.
Murray began his season in Biella, Italy on the ATP Challenger Tour, losing in the final to Ukraine's Illya Marchenko on 14 February.
Murray, who missed the year's opening Grand Slam in Australia following a positive test for coronavirus, last played on the ATP Tour in Cologne in October when he suffered a first-round defeat by Fernando Verdasco.