World number one Novak Djokovic beat qualifier Ivan Gakhov in his first match in more than a month to reach the third round of the Monte Carlo Masters.
He had not played since 3 March, when he lost to Daniil Medvedev in the Dubai Tennis Championships semi-finals.
The Serb was not allowed to enter the United States for the Miami Open and Indian Wells Masters because of his Covid-19 vaccination status.
Djokovic, a 22-time Grand Slam champion, will face either qualifier Luca Nardi or 16th seed Lorenzo Musetti, both of Italy, in the last 16 on the Monaco clay.