The 23-time major champion was back in Paris for the first time since 2016 and her win sets up a second round encounter with 17th seed Ashleigh Barty.
Williams’ serve was the strongest part of her game, winning 80 percent of her first serves and hitting 29 winners, good numbers for a first major match in 17 months.
Pliskova hit 15 aces while claiming 75 percent of her first service points. Her undoing was 33 unforced errors, but she counterbalanced that with 34 winners.
Williams grabs razor-thin opening set
It was always going to be a display of power tennis with big serving throughout and neither player disappointed as Williams' first serve looked awfully close to being in top form while Pliskova used her lefty advantage to send the American the wrong way.
The lower-ranked of the two Pliskova sisters served up nine aces through five service games as the first 11 games in total did not see either player have a break point.
Finally, serving to stay in the set, the Czech faced set point, but an ace down the middle and bigger serving after that sent the opener into a tiebreak.
She used that momentum to blast a forehand winner and claim the first mini-break, her lead extended to 3-0 with two easy points on serve.
Williams would rally back and at 3-3, a backhand winner gave her the lead for good. She extended her lead to 6-3 and although Pliskova would save one set point, her mishit forehand on the second closed out the tiebreak in Williams' favour.
Williams wraps up match after falling behind an early break
Shaking off the disappointment of the opening set, Pliskova held to love and grabbed the first break of the match with a bushel of forehand winners to take a 2-0 lead. A double fault at 15-40 handed the break back to Williams and returned the set to level terms.
After a hold, the three-time Roland Garros champion claimed the lead for good when, at 30-40, her change of pace forehand forced the Czech to dump a backhand into the net, putting the score at 3-2. Uncharacteristically, Williams was again broken, but the crucial game of the match immediately followed.
After an ace gave Pliskova a 40-0 lead, a pair of forehand winners from Williams brought the game back to deuce and on break point, it was the world number 70's forehand letting her down, handing the initiative back to the American.
A love hold and a quick 0-30 lead put Williams two points from victory, but Pliskova reversed momentum one last time and held which was followed by a trio of break points, saved with big serving and powerful groundstrokes.
Finally, on match point, Pliskova dumped one last forehand into the net, bringing to a conclusion a most entertaining encounter that lasted 1 hour, 45 minutes.
Serena assesses her performance following the victory
Speaking with the media after her win, Williams said: “I feel like I'm on the right track. I have been putting a lot of work in on the court, off the court, on the court, on the court, off the court, that's kind of been my life. I have been really enjoying it".
She felt that she is “serving pretty good, better than a few months ago."
Williams added: "I definitely feel like I can still improve on that a great deal, like, my speed on my serve isn't as fast as I normally hit it, but also I didn't really try to hit it that much. I was going more for placement".
Ever the perfectionist, Williams reminded the media that: “you know me. I really feel like I can improve on literally everything, and that's the great thing, as I feel like I can improve and there is room for improvement, and that means I can get better.”
She also commented on life as a mom and how it has impacted her career: "I'm really fortunate enough that I can plan my days and I can plan, like, my career. I feel like most moms don't have the opportunity that I do.
“I plan my day, like, training is X of time. Then I spend all this time with Olympia. And then if I need to train again, I have X time in training because of her nap schedules".
She concluded by saying: “my priority is Olympia. No matter what, that's my priority. I have given tennis so much, and tennis has actually given me a lot, and I couldn't be more grateful. She's my priority, and I work everything around her.
“I want her to know that I really try to put her first in my life, along with God and my family. I really try to put that first in my life. I feel like everything else will fall into place, and it has. I feel like it's all going to work out.”