The 22-year-old Pole, already a winner in Paris in 2020 and 2022, won her fourth Grand Slam title, with the 2022 US Open as well.
Big surprise of the fortnight, Muchova, 43rd in the world before the tournament, played at 26 years old his first final in a major tournament.
Swiatek has never been beaten in a Grand Slam final, even though she was pushed to her limits by the Czech player.
It will consolidate its place as world No. 1 on Monday, which it will occupy for the 63rd week in a row. Swiatek rose to the top of the women's rankings on April 4, 2022 after Ashleigh Barty retired.
She also became the youngest player since Monica Seles (1990, 1991, 1992) to retain her title at Roland Garros.
The Pole is also the third player from the Open era (1968) to win her first four Grand Slam finals, after Monica Seles and Naomi Osaka.
Only Serena Williams was younger when she won her fourth Major, at the 2002 US Open.
After a quiet tournament, Iga Swiatek found a very strong resistance in the final, against an atypical player who almost derailed her.
In the first set, the Pole quickly broke away 3-0 and easily won it 6-2.
In the second set, while the crowd took up Muchova's cause, it all started exactly as in the first, with Swiatek leading 3-0. But this time, the Czech managed to destabilize her opponent. After tying at 3-3, she missed a first opportunity to close on her serve at 5-4 before finally succeeding, still on her stake, at 6-5.
On his way Muchova won the first two games of the decisive set without leaving a single point to Swiatek. But the latter stayed in the match and came back to 2-2.
At 5-4, the world No. 1 forced Muchova to serve to stay in the match, the Czech then losing on a double fault.
© 2023 AFP