Novak Djokovic made the second round of the French Open after beating Brazilian qualifier Rogerio Dutra Silva.
The former world number one seeded 20th at Roland Garros, went 2-0 down at the start of the first two sets but recovered to come through 6-3 6-4 6-4.
The injury-hit Serb, 31, has not won a Grand Slam title since his victory in Paris in 2016.
Meanwhile, Stan Wawrinka, another former champion who has struggled with injury, lost his opener.
The Swiss 23rd seed, who overcame Djokovic in the French Open final in 2015, was beaten 6-2 3-6 4-6 7-6 (7-5) 6-3 by Spaniard Guillermo Garcia-Lopez.
That defeat means Wawrinka will fall from world number 30 to outside the top 250 when the new standings are released on 11 June.
Elsewhere, the match between number one seed and 10-time champion Rafael Nadal and Italian Simone Bolelli was suspended because of rain.
The Spaniard had a two-set lead but was 3-0 down in the third set against the impressive Bolelli when the weather started to worsen.
Austrian seventh seed Dominic Thiem overcame Ilya Ivashka of Belarus 6-2 6-4 6-1. Thiem will now face Greece’s Stefanos Tsitsipas, ranked 39th, while Djokovic takes on Spain’s Juame Munar, the world number 155.
Djokovic, now ranked 12th, said before the tournament that his confidence had been knocked after suffering a recurring elbow problem, which required surgery in January.
He returned to training in March and fell to successive first-round defeats at Indian Wells and the Miami Open.
But the 12-time Grand Slam champion reached the semi-finals of the Italian Open earlier this month and looked fairly comfortable against Dutra Silva, the world number 134.
The Brazilian got off to the best possible start by breaking his opponent in the opening game, before Djokovic got into his stride.
Dutra Silva had his opponent rattled in the third set after they exchanged breaks, and Djokovic slammed a loose ball against the advertising boards in anger before apologising to the crowd for his reaction.
In the end, the Serb brought up three match points and served it out at the second attempt.