23:36 CET - In the last match of the day in Madrid, American Peyton Stearns has beaten Australia's Kimberly Birrell 5-7, 6-3, 6-4 in an epic to move into the second round.
That concludes the action in Spain for today, but be sure to tune back in tomorrow as the women's first round continues and the men get started in Madrid.
20:58 CET - Lulu Sun has come back to beat Varvara Gracheva 3-6, 6-1, 6-4 in just under two hours to book her place in the second round in Madrid.
20:47 CET - Camila Osorio has beaten fellow Colombian Emiliana Arango 6-3, 6-3 to progress to the second round in Madrid. Osorio is coming off winning the tournament in Bogota earlier this month.
19:41 CET - World number 40 Katie Boulter has advanced to the next round after fighting back from a set down to beat Katerina Siniakova 4-6, 6-2, 6-1.
17:15 CET - Marie Bouzkova and Jessica Bouzas Maneiro are both through to the second round after beating Renata Zarazua and Mayar Sherif, respectively.
15:21 CET - Naomi Osaka has fallen at the first hurdle, being beaten 4-6, 6-2, 6-4 by Lucia Bronzetti.
It was the Japanese player's first match in a month, and not how she would have wanted to begin her clay-court season.
13:30 CET - The first two matches of the tournament are over, and they've seen young talent Alexandra Eala beat Viktoriya Tomova 6-3, 6-2 and Caroline Dolehide claim a 6-4, 6-4 victory over Elina Avanesyan.
11:40 CET - If you missed any of the tennis last week, or even yesterday, catch up on who the big winners and losers were on the ATP and WTA circuits with our wrap-up in The Base Line.
07:25 CET - Hello and welcome to Flashscore's coverage of the opening day of the Madrid Open!
The women are getting the ball rolling in the Spanish capital with 10 matches over the course of the day, and the first of them will get underway at 11:00 CET when Elina Avanesyan takes on Caroline Dolehide and Viktoriya Tomova faces Alexandra Eala.
The standout clash of the day will see Naomi Osaka go up against Lucia Bronzetti, and that should begin at around 12:30.