16:45 CET - Four hours on from a widespread power outage striking the Spanish capital, play at the Madrid Open has been cancelled for the day.
"For reasons beyond the control of the organisation and in order to guarantee general safety, the nationwide power-cut experienced in Spain on Monday 28 April has forced the cancellation of both the day and night sessions at the Mutua Madrid Open," the tournament said on social media platform X.
We'll be back with a fresh new Tennis Tracker tomorrow morning, with hopefully the power back up and running in Madrid and a bumper day of action to look forward to!
12:56 CET - Matteo Arnaldi has overcome Damir Dzumhur 6-3, 6-4 to move into the last 16, just before play was suspended in Madrid due to a loss of power in the whole of the capital. It is unclear when action will resume.
12:43 CET - 17-year-old starlet Mirra Andreeva is into another WTA 1000 quarter-final this season after a relatively straightforward, 6-1, 6-4 win over Yuliia Starodubtseva. She will face Coco Gauff in a heavyweight last-eight clash.
12:32 CET - Coco Gauff is the first winner of the day in Madrid, putting in one of her best performances of the season to ease past Belinda Bencic, 6-4, 6-2. She is through to her first quarter-final in the Spanish capital.
10:55 CET - Play is set to get underway in the Spanish capital in the coming minutes, with Mirra Andreeva, Coco Gauff, Grigor Dimitrov and Matto Arnaldi heading onto court first.
08:00 CET - Good morning and welcome back to the Tennis Tracker on this Monday morning!
The last 16 is getting underway today in Madrid in the women's tournament, and some of the contests promise to be fantastic affairs. Coco Gauff is set to go head-to-head with Belinda Bencic this morning, before Diana Shnaider takes on defending champion Iga Swiatek.
Australian Open champion Madison Keys faces Donna Vekic this afternoon in what is surely going to be a huge-hitting affair. Mirra Andreeva, Marta Kostyuk, Elina Svitolina and world number one Aryna Sabalenka will all also take to the court throughout the day.
Over on the men's side, there is also plenty to look forward to. Grigor Dimitrov and Matteo Arnaldi - who is coming off the back of beating Novak Djokovic - are the first players on court, while Frances Tiafoe, Cameron Norrie and Alex De Minaur will also aim to reach the last 16.
But in the standout matches, world number six and Indian Wells champion Jack Draper meets Italian Matteo Berrettini, Stefanos Tsitsipas comes up against Lorenzo Musetti in a rematch of their Monte Carlo quarter-final, and Tommy Paul does battle with Karen Khachanov.
A sensational day of tennis, you can follow the women's action here and the men's here.