Arriving on Philippe Chatrier Court in a black catsuit, offset with a pinkish-red waistband, Williams trailed 0/3 in the first-set tiebreaker.
Williams admitted her eye-catching, figure-hugging black catsuit was inspired by the smash hit Black Panther movie but was also meant to help women with post-natal complications.
The new outfit also was reminiscent of the tight-fitting white bodysuit that American player Anne White wore at Wimbledon in 1985.
"I have been wearing trousers a lot when I play so I can keep the blood circulation going". She backed out of the recent Madrid and Rome tournaments, saying she didn't think she was ready to play.
Competing as a mother for the first time at a major - and only about nine months after giving birth to her daughter, Alexis Olympia, then dealing with postpartum complications - Williams served up 13 aces and broke Pliskova's serve three consecutive times to cruise to victory.
The three-time French Open champion and 23-time Grand Slam victor will next take on Australia's Ash Barty in the second round.
The next 2 games saw breaks of serve traded, resulting in Serena remaining ahead 4-3, as both players serves deserted them.
Williams referred to what she wore Tuesday as the "catsuit - the new version, 2.0".
Williams returned to the court in Paris and defeated Kristyna Pliskova in straight sets 7-6, 6-4. "It's exciting. I think the catsuit is-you can't beat a catsuit, right?", she said during a post-match interview with The Tennis Channel.
"Just literally not sure if I was going to make it or not at several different times", Williams said. "In the beginning it was hard to learn her nap schedules... because I don't want her to ever feel like I'm not around".
Serena Williams on her way to victory over Kristyna Pliskova.
Then came singles matches that actually counted, with two wins at Indian Wells, California, before a loss to Venus, followed by a first-round loss at the Miami Open on March 21. It definitely has little functionality to it.
In every category, Serena's achievements dwarf her opponent's, bar one - Pliskova holds the WTA record for aces in a single match: 31 at the 2016 Australian Open.
Williams and Barty have played only once previously, with the American posting an easy win at the 2014 Australian Open.
Without a win at Roland Garros since 2015, Gavrilova was staring down the barrel of another painful premature exit at the hands of Sorana Cirstea before rallying to a 4-6 7-6 (7-4) 6-3 win over the feisty Romanian.