She had been away from grand slams for 16 months, but Serena Williams said she felt like "a warrior princess" as she returned to winning ways at the French Open Tuesday.

The 36-year-old defeated Czech Kristyna Pliskova 7-6 (7-4) 6-4 in her first grand slam match since becoming a mom, but it was her eye-catching black catsuit that had tongues wagging.

Laughing as she made reference to the fictional nation in sub-Saharan Africa, which is home to superhero Black Panther from Marvel Comics, Williams told reporters: "I feel like a warrior in it, like a warrior princess, a queen from Wakanda maybe.

"It was comfortable to wear. I'm always living in a fantasy world. I always wanted to be a superhero, and it's kind of my way of being a superhero. I feel like a superhero when I wear it."

Williams hit 13 aces in the match.

The skintight outfit also serves a serious purpose, helping the 23-time grand slam champion's blood circulation after a difficult childbirth.

In an opinion piece for CNN in February, the former world No.1 described how she almost died while giving birth to her daughter, Olympia.

Williams, who gave birth in September, added: "I had a lot of problems with my blood clots. God, I don't know how many I have had in the past 12 months. So there is definitely a little functionality to it.

"I have been wearing pants a lot when I play so I can keep the blood circulation going."

Williams 'on the right track'

Though she is the most successful female player of the open era, with a ranking of 451 in the world she is not seeded in Roland Garros.

Hitting 13 aces and lifting her game when trailing in a first-set tiebreak, the American overcame a player 381 places above her in the rankings in an hour and 45 minutes. Australian Ashleigh Barty awaits her in the second round.

In an Instagram post after her victory -- her first match on clay since the 2016 French Open final -- Williams wrote: "Catsuit anyone? For all the moms out there who had a tough recovery from pregnancy—here you go. If I can do it, so can you. Love you all!!"

Williams, who won the 2017 Australian Open in the early stages of pregnancy. told reporters she felt she was "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," said Williams, who had arrived at the French Open on a two-match losing skid and with no warmup matches on clay.

"I have been really enjoying it. Hopefully the results continue to show."