Novak Djokovic was given a stern test by Steve Darcis but came through it to record his 50th win at the French Open and reach the third round.
The world number one is the seventh man to notch his half-century at Roland Garros and the only one not to have yet won the title.
Djokovic also becomes the third player in the Open era to reach 50 wins at all four grand slams, joining Serena Williams and Roger Federer.
He was made to work harder than might have been expected against qualifier Darcis, who famously beat Rafael Nadal at Wimbledon in 2013, before coming through 7-5 6-3 6-4 in two hours and 17 minutes.
The Belgian, whose ranking has slipped to 161 because of injury, delighted the crowd with the variety in his game and drove Djokovic to distraction at times.
The Serbian made a flying start, winning the opening three games, but Darcis got back on level terms and came close to forcing a tie-break in the opener.
Djokovic never really appeared in danger of dropping a set but, unlike potential semi-final opponent Nadal, has yet to hit top form in Paris.