Roger Federer eased through his French Open return with a straight-set win over Uzbekistan's Denis Istomin.
The 20-time Grand Slam champion had not played at Roland Garros since 2019 and was playing his first match at a major in 16 months after a knee injury.
The 39-year-old Swiss played smoothly and confidently as he won 6-2 6-4 6-3.
Meanwhile, Russian second seed Daniil Medvedev ended his misery at Roland Garros as he beat Alexander Bublik for his first win on the Paris clay.
Medvedev, 25, won 6-3 6-3 7-5 against Kazakhstan's Bublik, ending a run of four successive defeats in round one.
Elsewhere in the men's singles draw on Monday, Croatia's Marin Cilic set up a second-round meeting with Federer following a 7-6 (8-6) 6-1 6-2 win against Frenchman Arthur Rinderknech.
Belgian 13th seed David Goffin was beaten in straight sets by Italian 19-year-old Lorenzo Musetti, the Lyon Open semi-finalist winning 6-0 7-5 7-6 (7-3) to claim his first victory at a Grand Slam.
Norwegian 15th seed Casper Ruud, 22, overcame Benoit Paire 5-7 6-2 6-1 7-6 (7-4), while John Isner won an all-American match against Sam Querrey 7-6 (7-2) 6-3 6-4.
