a much harder time getting past the Romanian spin-merchant in her Indian Wells opener, showed no sign of the knee injury that forced her to forfeit her quarter-final in California last week.
“It was a little sore in practice, but it was OK today,” Williams said of her knee. “I really didn’t feel it today, to be honest.
“Once you step out on the court you have so much adrenaline going. The adrenaline kind of kills it. So I was surprised. I felt pretty good,” added Williams, who is seeking an eighth Miami crown.
The 33-year-old American star next faces 15-year-old compatriot Catherine “CiCi” Bellis.
Bellis advanced with a 6-2, 6-1 win over 29th-seeded Zarina Diyas on Friday.
In other men’s matches, Japanese fourth seed Kei Nishikori defeated Russian Mikhail Youzhny 6-2, 6-1.
Canadian fifth seed Milos Raonic beat Teimuraz Gabashvili 6-1, 6-4 while Spanish sixth seed David Ferrer beat Argentine Federico Delbonis 6-1, 6-1.
French 11th-seeded Jo-Wilfried Tsonga celebrated his return from a lingering arm injury with a 6-4, 3-6, 6-3 win over American Tim Smyczek.
Tsonga, who hadn’t played since France’s Davis Cup tie against Switzerland in November, said he was satisfied with his 2015 debut.
“I didn’t expect to play my best tennis today ever, but I’m happy the way I managed my match,” said Tsonga. “I played pretty solid, I just had a little hole in the second set.”
While Williams looked sharp in her second-round match postponed from Friday by rain, sixth-seeded Canadian Eugenie Bouchard fell at the first hurdle, beaten 6-0, 7-6 (7/4) by German qualifier Tatjana Maria.
In women’s third-round play, fourth-seeded Dane Caroline Wozniacki, Russian eighth-seed Ekaterina Makarova and ninth-seeded German Andrea Petkovic all advanced.
Venus Williams also booked a fourth-round berth, with a 6-4, 7-6 (7/3) victory over Australian Samantha Stosur.