PREVIEW-Tennis - Top seeds take centre stage on day three at Roland Garros

Defending champion Rafa Nadal and Serbia's Novak Djokovic headline day three of the French Open on Tuesday, with women's top seed Ash Barty also in first-round action at Roland Garros.

Nadal, who is seeking a record-extending 14th title at his favourite Grand Slam, is seeded third this year and in the same half of the draw as top seed Djokovic.

Winning the title will move Nadal past Roger Federer at the top of the all-time list of men's Grand Slam champions, with 21.

The Spaniard begins his campaign on Court Philippe Chatrier against Australia's Alexei Popyrin, who he beat in straight sets in the last-16 of the Madrid Masters in March.

Djokovic, who lost to Nadal in last year's French Open final, faces American Tennys Sandgren in the evening session.

The Serb has beaten Sandgren in all three of their previous meetings, with his most recent victory over the American coming at last year's ATP Masters tournament in Cincinnati.

Barty, the 2019 champion, opted not to defend her title last year, citing concerns over the COVID-19 pandemic and a lack of training time in an abbreviated season.

The Australian world number one opens her quest to regain her crown against unseeded American Bernarda Pera, in the first career meeting between the two.

Men's ninth seed Matteo Berrettini is in action on Court Simonne Mathieu, where he will take on Japanese qualifier Taro Daniel, while women's ninth seed Karolina Pliskova squares off against Croatia's Donna Vekic on Court Suzanne Lenglen.