All of the Top 20 players in the Hologic WTA Tour singles rankings are on the entry lists for the next two WTA 1000 events on the calendar: the Mutua Madrid Open and the Internazionali BNL d'Italia.

The first three WTA 1000 events of the season were contested on hard court, but now the circuit moves to clay, where World No.1 Iga Swiatek leads the two fields for the top-tier events on the dirt.

Swiatek has yet to be defeated at the WTA 1000 tournaments this season, taking the first three titles. She won her first title of the year in Doha, then swept the Sunshine Double of Indian Wells and Miami en route to a World No.1 debut.

The Mutua Madrid Open will take place as the first clay-court WTA 1000 of the season, with the main draw starting on Thursday, April 28 and ending on Saturday, May 7. Centered around the Caja Magica court, Madrid has been one of the flagship WTA 1000 events since 2009.

Swiatek is joined on the Madrid entry list by defending champion and World No.4 Aryna Sabalenka as well as their fellow Top 5 residents No.2 Barbora Krejcikova, No.3 Paula Badosa and No.5 Maria Sakkari.

The rest of the current Top 10 joins them on that entry list — Anett Kontaveit, Karolina Pliskova, Danielle Collins, Ons Jabeur and Garbiñe Muguruza.

Reigning US Open champion Emma Raducanu and 2021 US Open runner-up Leylah Fernandez are also entered, as is fellow teen Coco Gauff.

In addition to last year's titlist Sabalenka, former champions Simona Halep and Petra Kvitova are entered in Madrid. Halep has won the title twice (2016 and 2017) and Kvitova is a three-time champion (2011, 2015 and 2018).

Former World No.1 players Angelique Kerber and Victoria Azarenka are also entered in the main draw, as well as additional Grand Slam champions Bianca Andreescu, Jelena Ostapenko and Sloane Stephens.

Champion's Reel: How Iga Swiatek won Rome 2021

2021 Rome

The Internazionali BNL d'Italia follows in Rome from Monday, May 9 to Sunday, May 15. Dating back to 1930, the event is one of the longest-standing clay-court tournaments, and all of the Top 20 will be quickly back in action following Madrid.

Swiatek returns as the defending champion. Last year, she won her first career WTA 1000 title in Rome with a 6-0, 6-0 victory over 2019 champion Karolina Pliskova in the final.

In addition to Swiatek and Pliskova, the other former Rome titlists on the entry list are Halep (2020) and Elina Svitolina (2017 and 2018).

Along with all of the Top 10 listed above, Raducanu, Fernandez and Gauff are scheduled to play, as are Grand Slam winners Andreescu, Ostapenko, Kvitova, Kerber and Azarenka.

Former World No.1 and four-time Grand Slam champion Naomi Osaka also features in the Rome main-draw entries. Osaka is back up into the Top 40 after her run to the WTA 1000 Miami final.