Second-seeded Kristina Mladenovic of France opened with a 6-2, 6-3 victory over American Varvara Lepchenko in a first-round match in the women's draw of the Abierto Mexicano Telcel tournament in Acapulco, Mexico.
Borna Coric of Croatia defeated wild-card Lucas Gomez of Mexico 6-1, 6-1.
Fifth-seeded David Goffin, who is No. 11 in the world rankings, routed Stephane Robert of France 6-1, 6-2 in an evening match.
Mladenovic had no problems with Lepchenko, taking 3-0 leads in each set and remaining in control of the match on center court.
"I was trying to stay tough in my head, just trying to work for every single point, every game," Mladenovic said. "I was just trying to go for it, and Varvara is a tough player as well. Very happy with this first win."
Advancing to the second round in the women's draw was eighth-seeded Andrea Petrovic of Germany. She rallied from a set down for a 2-6, 6-1, 6-3 victory over American Jamie Loeb.
"I've been here for a week already so I've been practicing for a long time," Petkovic said. "I don't remember the last time I waited this long for a match. So at the beginning I was a bit tight, because also she had been through qualifying here
"She was playing really fast and I needed some time to get used to it. In the second and third set -- after some rough patches -- I think it was pretty good."
Seventh-seeded Lesia Tsurenko of Ukraine coasted to a 6-2, 6-1 win over Chloe Paquet of France.
In an all-American matchup, Shelby Rogers topped Louisa Chirico 6-2, 6-2. But two other American dropped their opening matches. Heather Watson of Great Britain downed qualifier Bethanie Mattek-Sands of the United States 7-5, 7-3 and Pauline Parmentier of France eliminated Nicole Gibbs 7-5, 6-7 (6), 6-2.
In the final match of the evening, Kristen Flipkens of Belgium dominated the third set in a 7-5, 6-7(7), 6-1 victory over Renata Zarazua of Mexico.