Top seed Maria Sharapova dodged the showers on her way to a 6-3, 6-2 victory over Taiwan's Chan Yung-Jan to set up a third round encounter against Venus Williams at the Sony Ericsson Open on Saturday.
Sharapova's match was briefly interrupted by rain, with the players returning mid-way through the second set before the Russian world number two went on to seal the win despite 30 unforced errors in windy conditions.
"Year-in year-out, the conditions are the same, they are to be expected," the 19-year-old told reporters.
"You have to adjust in the first match.
"It's not easy, but mentally I'm ready. I was a little up and down. You're never completely there in the opening match, but I'm sure it will get better."
Playing in just her third tournament since last year's Wimbledon, the unseeded Williams sat through a four-hour rain delay before defeating Russian Maria Kirilenko 6-3, 6-3.
Her 13th-seeded sister Serena advanced by the same scoreline against Russian Anastasia Rodionova.
"I'm so ready, I've been training every day and I am tired of it," Venus told reporters.
"It gets a little bit redundant and tiring. The easiest part of tennis is playing the tournaments for me."
Men's top-seeded holder Roger Federer regained his winning touch after his surprise second round defeat at last week's Pacific Life Open, easing past American teenager Sam Querrey 6-4, 6-3
Federer, playing the event for the ninth straight time, improved to 25-6 in Miami, having won the last two titles and 12 matches.
TIGER WATCHES
The Swiss player's last defeat in Miami came to the then number 34-ranked Rafael Nadal of Spain, now his main rival.
Golfing great Tiger Woods greeted Federer in the players' lounge before the taking his seat in the stadium to watch the delayed match.
"I'm happy he comes out during a tournament," Federer told reporters. "I don't know if golfers are more serious than we tennis players.
"But I went out to see his practice and it's great that he comes to watch tennis. It's a great honour for our sport."
Swiss women's fifth seed Martina Hingis earned a 6-3, 6-2 second round victory over Czech Iveta Benesova, but her compatriot Patty Schnyder was upset 6-1, 6-4 by world number 56 Kaia Kanepi of Estonia.
Eighth seed Nicole Vaidisova beat Michaella Krajicek of the Netherlands 4-6, 7-5, 6-2. Russian Yaroslava Shvedova shocked Serb 12th seed Ana Ivanovic 7-5, 6-4.
In the men's second round, seventh seeded Croatian Ivan Ljubicic was untroubled by Italy's Filippo Volandri in a 6-3, 6-2 win.
But German Tommy Haas, winner of 15 of his previous 17 matches, was knocked out 6-4 6-4 by the 95th-ranked Colombian Alejandro Falla, who was only in the main draw as a lucky loser.
Argentine number 11 David Nalbandian beat Vince Spadea 6-3, 6-4 while 15th seed Richard Gasquet won an all-French contest over Florida-based Sebastien Grosjean 6-4, 0-6, 6-2.
"Today was tough conditions, all windy and everything," Nalbandian told reporters. "If I win one or two more matches and get more confidence, maybe I can be dangerous."
He will next face Finland's Jarkko Nieminen, who won 6-0, 6-0 against Russian Evgeni Korolev.