Indian Wells marks Serena's first WTA sanctioned tournament in 14 months after she gave birth to her daughter, Alexis Olympia Ohanian Jr., on the first of September past year.
Serena won 54 percent of her second-serve points and broke Bertens's serve six times.
Collins, ranked 116th and making her first appearance in the main draw, is just starting her second year on the WTA Tour.
Keys hasn't made it past the fourth round at Indian Wells in eight tries.
After her second round win over Kiki Bertens, Serena said she "would prefer to play someone else, anybody else, literally anybody else, but it has to happen now".
Serena and Venus have faced each other 28 times in professional tournaments, the most recent being the aforementioned Australian Open final in 2017.
According to TMZ, Williams a filed legal documents to trademark "Aneres" (Serena spelled backwards-in case you didn't notice) for another fashion line. "You know, we can always stay in the tournament longer if the both of us are in the tournament", Serena said.
"It's a huge difference to play her in the semi-finals or even the quarter-finals or a final as opposed to the third round". In fact, it's the first time they've met before the Round of 16 since their very first head-to-head matchup more than 20 years ago.
Serena chose to return in 2015, whilst Venus came back to Indian Wells in 2016. "It's actually something that I really enjoy and that I have a lot of fun with", she told Vogue in 2015.
Venus' last defeat of her younger sister was at the Canadian Open in 2014, where she prevailed in a three-set semi-final.
The 23-year-old Svitolina advances to the third round where she will face Spaniard Carla Suarez Navarro who beat Hsieh Su-Wei, of Taiwan, 6-4, 2-6, 6-3.
The sisters' father was then accused of fixing matches between his daughters and predetermining who would win on any particular day.