The third seed had to struggle with 6-foot-5 Daniel Brands on Day 2 at Roland Garros, but the clay-court king fought back to beat the German 4-6, 7-6 (7-4), 6-4, 6-3 in 2 hours, 54 minutes on. Nadal broke Brands three times, while the German had only one break.
Nadal is 38-2 this year, including trips into finals in all eight of his 2013 events. He is seeking his seventh title of the season.
Earlier Monday Jo-Wilfried Tsonga, sixth-seeded French crowd favorite and former Australian Open runner-up, excused Slovenian Aljaz Bedene 6-2, 6-2, 6-3.
Also Monday in other action involving top seeds, No. 10 Marin Cilic of Croatia defeated German Philipp Petzschner 6-1, 6-2, 6-3. No. 13 Kei Nishikori of Japan whipped Canadian Jesse Levine 6-3, 6-2, 6-0.
Some other opening-round winners: France's Edouard Roger-Vasselin, German Tobias Kamke and Dutchman Igor Sijsling.