The first day of second round action saw straight sets wins for the two pre-tournament favourites, while Serena Williams quest for a record-equalling 24th Grand Slam title came to a premature end as she withdrew from her second round match with Bulgaria's Tsvetana Pironkova.

On the women's side, top seed Halep faced fellow Romanian Irina Camelia-Begu and dispatched her compatriot 6-3 6-4.

Other top women's seeds did not have things so easy with third seed Elena Svitolina of Ukraine overcoming a second set capitulation in the first match of the day on the main Court Philippe Chatrier to beat Mexican qualifier Renata Zarazua in three sets.

After Svitolina took the first set 6-3, world number 178 Zarazua took the second 6-0 before Svitolina rediscovered her form and took the decider to complete a 6-3 0-6 6-2 win.

Another remarkable encounter saw fifth seed Kiki Bertens of the Netherlands overcome Italy's Sara Errani in three sets in a match that lasted just over three hours.

Bertens left the court in a wheelchair after suffering what she claimed were severe bouts of cramp throughout her body during the 7-6 3-6 9-7 win.

In a media conference after the match Errani accused her opponent of exaggerating her injuries, with Bertens saying that she could not understand Errani's accusations.

The Italian had problems of her own during the match, resorting to underarm serves on a number of occasions after struggling with her ball toss while attempting to serve.

The women's draw lost two high-profile names with Williams withdrawing prior to her match with Pironkova citing an achilles injury, and tenth seed and US Open runner-up Victoria Azarenka of Belarus, the tenth seed, being soundly beaten by Anna Karolina Schmiedlova of Slovakia 6-2 6-2.

Among the other women's seeds in action were 23rd seed Yulia Putintseva of Kazakhstan, who was beaten 3-6 6-1 6-2 by Nadia Podoroska of Argentina and 25th seed Amanda Anisimova of the United States, who thrashed compatriot Bernarda Pera 6-2 6-0 in a match moved to the main Phillippe Chatrier court following Williams' withdrawal.

On the men's side, 12-time Roland Garros champion Nadal looked in ominous form as the Spaniard comprehensively beat American Mackenzie McDonald 6-1 6-0 6-3.

US Open champion Dominic Thiem, the third seed from Austria, also won in straight sets beating American Jack Sock 6-1 6-3 7-6.

Elsewhere, in what proved one of the best contests of the day on the main court, fifth seed Alex Zverev of Germany battled his way to a 2-6 6-4 7-6 4-6 6-4 win over home player Pierre-Hugues Herbert, in a match that lasted four hours.

2015 French Open champion Stan Wawrinka of Switzerland, the 15th seed this year, also advanced to round three after beating Germany's Dominik Koepfer 6-3 6-2 3-6 6-1.

Two men's seeds were eliminated on the fourth day of action in Paris with American John Isner, the 21st seed, falling to a 6-4 6-4 2-6 6-4 defeat to compatriot Sebastian Korda, while 23rd seed Benoit Paire of France was beaten 7-6 4-6 6-3 6-1 by Argentina's Federico Coria.