With the men's encounter between Frenchman Gael Monfils and Czech Tomas Berdych dragging on over on Chatrier Court, the Russian second seed's match was moved to the Suzanne Lenglen arena where Sharapova enjoyed a 54-minute stroll.
She ended her opponent's ordeal with a crosscourt backhand winner, with some spectators having barely had time to sit down.
Sharapova next faces Canada's Eugenie Bouchard.
Chinese sixth seed Li Na was kept on her toes as she reached the second round with a 6-3 6-4 victory over Spain's Anabel Medina Garrigues.
Li, the 2011 Roland Garros champion who had never beaten Medina Garrigues in three previous claycourt meetings, was never allowed to let her guard down by the world number 68 on a sunsoaked Court Philippe Chatrier, but she prevailed on her first match point after one hour 44 minutes.
Li opened a 4-0 lead in the first set before a resilient Medina Garrigues threatened a comeback by breaking back twice.
The Spaniard opened a 2-0 lead in the second set but could not capitalise on her advantage as Li roared back to win four games in a row, relying on a series of booming forehand winners.
Medina Garrigues levelled for 4-4 before dropping serve in the ninth game. Li sealed the win when Medina Garrigues fired a forehand long..
Li will next face American Bethanie Mattek-Sands.
Former world number one Wozniacki, who came into the tournament on the back of a poor run on clay this season, looked like a possible scalp for the improving 19-year-old, but the Dane took full advantage of an error-strewn performance from the Brit.
Wozniacki was the more consistent in the first set, and raced into an unassailable 4-1 lead in the second, allowing herself the luxury of giving away one of her breaks of serve before seeing out the match in just 71 minutes.
Wozniacki moves on to face Bojana Jovanovski next at Roland-Garros.
Fourth seed Agnieszka Radwanska, playing despite a painful shoulder, thrashed Israel's Shahar Peer 6-1 6-1. The Pole next faces Mallory Burdette of the USA.
21-Kirsten Flipkens (Belgium) beat Flavia Pennetta (Italy) 2-6 6-4 6-0
2-Maria Sharapova (Russia) beat Hsieh Su-Wei (Taiwan) 6-2 6-1
Francesca Schiavone (Italy) beat Melinda Czink (Hungary) 6-0 7-6(1)
Paula Ormaechea (Argentina) beat Tatjana Maria (Germany) 6-3 4-6 6-0
Garbine Muguruza Blanco (Spain) beat Karolina Pliskova (Czech Republic) 4-6 7-5 6-3
Eugenie Bouchard (Canada) beat Tsvetana Pironkova (Bulgaria) 6-1 7-6(2)
17-Sloane Stephens (U.S.) beat Karin Knapp (Italy) 6-2 7-5
Svetlana Kuznetsova (Russia) beat 22-Ekaterina Makarova (Russia) 6-4 6-2
Jana Cepelova (Slovakia) beat Christina Mchale (U.S.) 7-6(3) 2-6 6-4
Zheng Jie (China) beat Vesna Dolonc (Serbia) 6-4 6-1
8-Angelique Kerber (Germany) beat Mona Barthel (Germany) 7-6(6) 6-2
Magdalena Rybarikova (Slovakia) beat Pauline Parmentier (France) 6-0 6-1
Melanie Oudin (U.S.) beat 28-Tamira Paszek (Austria) 6-4 6-3
10-Caroline Wozniacki (Denmark) beat Laura Robson (Britain) 6-3 6-2
Bojana Jovanovski (Serbia) beat Barbora Zahlavova Strycova (Czech Republic) 6-3 6-2
Mathilde Johansson (France) beat Chanelle Scheepers (South Africa) 7-5 6-1
Elina Svitolina (Ukraine) beat Romina Oprandi (Switzerland) 6-3 4-6 6-1
Vania King (U.S.) beat Alexandra Cadantu (Romania) 7-6(3) 6-1
29-Varvara Lepchenko (U.S.) beat Mirjana Lucic-Baroni (Croatia) 6-1 6-2
Maria Teresa Torro (Spain) beat Julia Glushko (Israel) 6-2 7-5
20-Carla Suarez Navarro (Spain) beat Simona Halep (Romania) 3-6 6-2 6-2
Zuzana Kucova (Slovakia) beat 24-Julia Goerges (Germany) 7-6(8) 6-0
6-Li Na (China) beat Anabel Medina Garrigues (Spain) 6-3 6-4
Bethanie Mattek-Sands (U.S.) beat Lourdes Dominguez Lino (Spain) 6-4 6-1
Johanna Larsson (Sweden) beat Monica Niculescu (Romania) 6-2 6-3
4-Agnieszka Radwanska (Poland) beat Shahar Peer (Israel) 6-1 6-1
15-Roberta Vinci (Italy) beat Stephanie Foretz Gacon (France) 6-3 6-0
- Sports & Recreation
- Anabel Medina Garrigues
- Caroline Wozniacki