Iga Świątek was the defending champion, but lost to Sakkari in the quarterfinals. Świątek's loss marked the 14th consecutive year where the reigning French Open champion failed to defend their title, withJustine Henin being the last woman to do so in2007 (Świątek would end this stretch herselftwo years later).[4] It ensured the sixth consecutive French Open to feature a first-time major champion.[5] Świątek's loss also ensured that this was the first French Open and the third major in theOpen Era to feature all first-time major semifinalists,[6] and it was the first major in the Open Era in which six players made their major quarterfinal debuts.[7]
Serena Williams was the oldest woman in the Open Era to reach the fourth round; this was also the three-time champion's final French Open appearance before retiring from professional tennis the following year.[9][10] Sakkari andTamara Zidanšek became the first Greek woman and Slovenian player to reach the singles quarterfinals and semifinals of a major, respectively.[11][12][b]Coco Gauff was the youngest player to reach a major quarterfinal sinceNicole Vaidišová at the2006 French Open.[13]
The following are the seeded players. Seedings are based on WTA rankings as of 24 May 2021. Rankings and points before are as of 31 May 2021. Because the tournament was moved a week and points of the week of 10 June 2019 includes results only fromNottingham. Thedefending points from's-Hertogenbosch is not included towards on dropping points.
As a result of pandemic-related adjustments to the ranking system and changes to the WTA Tour calendar in 2020, players will have the following potential adjustments to their ranking points after the tournament:
Players who are defending points from the2019 tournament in which are higher will be dropped on 14 June 2021; those points will be replaced by the higher of their points from 2019 or 2020 (points from 2020 will still be valid at the end of the 2021 tournament because the2020 tournament delayed to four months in the normal scheduled calendar year; both 2019 and 2020 points are equaled within the same result will also be dropped on 11 October 2021).
Players who are defending points from the 2020 tournament will have those points replaced by 2021 points only if the latter are higher.
Players who have points from the 2020 tournament still counting towards their ranking on 14 June 2021 will have those points dropped on 11 October 2021 (52 weeks after the 2020 tournament); any 2020 points will be replaced by 2021 points at that time.
Players who are not defending points from either the 2019 or 2020 tournaments will have their 16th best result replaced by their points from the 2021 tournament.
Note that this is a different ranking adjustment system than the one being used by the ATP for the men's event.
†The player's 2019 points will be replaced by (or the player will continue to count) her 2020 points, which will be dropped on 11 October 2021, four months after the end of the 2021 tournament. §The player did not qualify for the tournament in 2019. Accordingly, points from her 16th best result are deducted instead.
^AlthoughMartina Navratilova was the women's singles champion at the French Open in1982 and1984, she won both titles whilst competing for the United States of America.
^Zidanšek became the first player representing Slovenia as an independent country following its independence fromYugoslavia in 1991.Mima Jaušovec, who the1977, did so when Slovenia was part of Yugoslavia.
Bold denotes the mandatory tournaments (WTA 1000) † –Tournaments are affected by theCOVID-19 pandemic * –Tournaments are introduced due to the impact of the COVID-19 pandemic