Coco Gauff beat Belinda Bencic 6-4, 6-2, and Mirra Andreeva beat Yuliia Starodubtseva 6-1, 6-4.
Gauff posted an Instagram story showing only an emergency light working in an otherwise dark locker room.
“No power where the showers are. So I’m about to take a shower and I’ll let you all know how it goes,” the American said.
Second-ranked Iga Swiatek “sat in the darkened players’ lounge, talking with members of her team,” ahead of her match against Diana Shnaider, the WTA Tour said.
Swiatek and Shnaider were scheduled to play in the main stadium after the Dimitrov-Fearnley match.
Spanish power grid operator RedElectrica said the Iberian peninsula was affected. It said the incident is being assessed and responded to.
The countries have a combined population of over 50 million people. It is not immediately clear how many people are affected.
