Angelique Kerber has won her last 13 matches, stretching back over half a decade, against her fellow Germans. The last time the two-time major champion lost to a compatriot was in the second round of Doha in 2013 - to Mona Barthel, her opponent today. Overall, Kerber leads the head-to-head against Barthel 3-2, including another first-round Roland Garros pairing in 2013 by a 7-6(6), 62 scoreline.
For the second year in a row, 2016 winner Garbiñe Muguruza opens her French Open campaign against a former champion. Last year, the Spaniard defeated 2011 champion Francesca Schiavone 6-2, 6-4; today, she starts against 2009 victor Svetlana Kuznetsova. Muguruza leads the head-to-head against the Russian 5-1: Kuznetsova captured their first meeting in Madrid in 2015, but the No.3 seed's dominance since then has included their only previous Roland Garros meeting (in the fourth round in 2016), as well as three meetings last year in Brisbane, Wimbledon and Cincinnati.
French No.1 Caroline Garcia's Roland Garros record coming into last year's event was a modest 3-6 - but her quarterfinal run was the catalyst for her rise from perennial Top 30 player into a legitimate Top 10 contender. Her opening opponent, Duan Yingying, is yet to win a professional match on clay at any level; the only set the Chinese player has won on the surface was in a 5-7, 6-2, 6-3 qualifying loss to Victoria Kan at the 2015 French Open.
No.30 seed Anastasia Pavlyuchenkova has played Polona Hercog three times to date - but only one of those matches was completed, their Monterrey second-round in 2010, won by the Russian 6-2, 6-3. In 2012, their Brisbane encounter ended in a Hercog retirement - and later that year, Pavlyuchenkova would be forced to retire from their Beijing match.
This is the 20-year anniversary of Serena Williams's first appearance at Roland Garros. Ranked No.27 at 16 years old, it was just Williams's second clay-court tournament ever following a quarterfinal run in Rome two weeks prior. The three-time French Open champion's Parisian debut was a 6-2, 1-6, 6-4 defeat of Jana Nejedly, and the American followed it by losing three games combined against Corina Morariu and No.15 seed Dominique Van Roost before falling 4-6, 7-5, 6-3 to eventual champion Arantxa Sánchez-Vicario.
Serena Williams is one of five mothers in this year's main draw. The other four - Victoria Azarenka, Kateryna Bondarenko, Mandy Minella and Tatjana Maria - have all already lost their opening matches. Williams, who gave birth to daughter Olympia in September, is ranked No.451 following two tournaments, Indian Wells and Miami in March. Azarenka, who had son Leo in December 2016, returned last June and is ranked No.84 after six tournaments; Minella gave birth to daughter Emma in October, resumed competition in February and is ranked No.286 after eight tournaments. Maria achieved a career-high ranking of No.46 as a mother last November, three-and-a-half years after returning; Bondarenko, who also came back from maternity leave in 2014, is yet to crack the Top 50 again.
Anna Karolina Schmiedlova is playing her first French Open since 2016. The Slovak notched up her first Top 30 victory here in 2014, over Venus Williams, and was the only player to win a set from Garbiñe Muguruza during the Spaniard's 2016 title run. Schmiedlova holds a 3-1 head-to-head lead over opening opponent Irina-Camelia Begu, including a win in their most recent clay encounter in the 2015 Rio de Janeiro semifinals.
Both champions and finalists of last week's warm-up tournaments in Strasbourg and Nurnberg are in action today: Anastasia Pavlyuchenkova, Johanna Larsson, Dominika Cibulkova and Alison Riske. Since Strasbourg's inception in 1987, five of its winners have immediately stumbled at the first hurdle in Paris: Radka Zrubakova (1991), Irina Spirlea (1998), Silvija Talaja (2000), Claudine Schaul (2004) and Monica Puig (2014). The furthest a Strasbourg champion has progressed at Roland Garros in the same year is Nicole Vaidisova's 2006 semifinal run.
In the four years that Nurnberg has been scheduled immediately preceding the French Open, two tournament champions have gone on to make the semifinals in Paris: Eugenie Bouchard (2014) and Kiki Bertens (2016).
Samantha Stosur has made at least the third round at Roland Garros every year since her maiden Grand Slam semifinal here in 2009. Her second-round match that year against Yanina Wickmayer is reprised as her opener today; the Australian won that encounter 6-3, 4-6, 6-4 and leads the overall head-to-head 4-2. In their most recent meeting, Stosur was forced to save a match point en route to a 2-6, 6-4, 7-6(6) win in the second round of Indian Wells in 2016.
— Garbiñe Muguruza (@GarbiMuguruza) May 28, 2018
— Carla Suarez Navarro (@CarlaSuarezNava) May 28, 2018
Jelena Ostapenko became the first defending Roland Garros champion to lose her first-round match in 13 years on Sunday. However, argues Matt Zemek at Tennis With An Accent, the lessons the Latvian learns from the loss could be invaluable in the long run.
No.1 seed Simona Halep enters Roland Garros attempting once again to win her maiden Slam title - now with three final defeats, all over three sets, hanging over her. Simon Cambers has talked to two other players who needed time to get the monkey off their backs for ESPN: Caroline Wozniacki, who became Australian Open champion in January eight years after first ascending to No.1, and Kim Clijsters, who lost her first four Slam finals - but won her next four.
All eyes are on Serena Williams as the 23-time Grand Slam champion returns to a major for the first time since giving birth. Watch the legend of the game go through her practice as she prepares to take on Kristyna Pliskova.