Williams, the No.10 seed at the Premier-level event, was the first to advance, blasting eight aces en route to a 62 61 win over No.21 seed Roberta Vinci.
"I played okay. I can definitely do better but I haven't played a lot," Williams said. "It's just about getting those matches. But I don't see Venus Williams making any excuses about not playing a lot, and she's doing excellent."
Williams did not watch her sister's upset over No.3 seed Petra Kvitova the night before. "I wasn't there - I played so early today, I needed to kind of not be there," she said. "I actually hate morning matches, but I always do my best at 11 or 10 o'clock matches. I always do excellent, so maybe I should like them.
"I have this app that's like WTA/ATP live score, so I was watching the live scores last night. It was really intense. I got a little nervous after she lost the second set, but then she raced through the third, so I was really excited."
No one has won Miami more than Williams - she has five titles here, tied for the all-time record with Steffi Graf. But she's still hungry for more success. "I need trophies," she said. "I want to add more and do more. There are records to break. I've just got to believe it. I do believe it. I just have to go from there."
The No.12-seeded Lisicki followed shortly after, completing a hard-fought 64 75 win over No.17 seed Peng Shuai. The two performed far differently on the biggest points - Lisicki converted five of six break points, Peng just three of 14.
"She hits the ball very hard, so you have to run down a lot of balls and be very consistent against her," Lisicki said of Peng. "I saved lots of break points too, and four set points in the second set, so I'm glad I closed it out in two sets."
Lisicki lives in Bradenton, Florida. "The weather here suits me well, and I live a few hours away from here, so it feels like a home tournament for me," she said. "I love coming here. I have lots of friends and people from the academy here."
Williams and Lisicki could move into the Top 10 after Miami, depending on the results in Week 2. Lisicki is a longer shot, but it is possible both could move into the elite, if Lisicki wins the title and Williams makes the semifinals or better (they would replace Vera Zvonareva and Andrea Petkovic).
Other early winners on Saturday were No.8-seeded Li Na, who won the last four games of each set to beat Iveta Benesova, 75 62, and Ekaterina Makarova, who won an all-unseeded battle against rising star Mona Barthel, 62 64.
Williams wasn't the only former No.1 and multiple Sony Ericsson Open champ to take the court, but she was the only one who won - Kim Clijsters, a winner here in 2005 and 2010, fought off six match points late in the second set but succumbed on the seventh to No.23 seed Yanina Wickmayer, 64 76(5).
"Yanina definitely started off much better and was more consistent throughout the two sets, and I wasn't," Clijsters said. "It was still close. In a way it's a little bit frustrating knowing you're playing not even 50% but it's still close. On one hand you're like, 'Ah, I could have beaten her.' But she played well today.
"I did feel she was getting nervous to finish off the match as well, so I had a few opportunities to get back into it and maybe win that second set."
"It was a special win for me today because she was one of my idols growing up," Wickmayer said. "I feel good. I'm getting more confidence every week."
Maria Sharapova, the No.2 seed, wrapped up the day session winners just before 6pm with a 64 62 win over American qualifier Sloane Stephens.