Madrid, April 29 -- Mirra Andreeva had just stepped up to the baseline to serve for a place in the Madrid Open quarter-finals when the power went out.

A sweeping outage left millions in Spain, Portugal and parts of France without power, causing chaos across many regions on Monday.

At the Spanish tennis tournament, the electronic line-calling system went down, with players and the chair umpire left to call the lines, while the scoreboards also went dark.

On the main court, where Britain's Jacob Fearnley was about to serve to stay in the match against Bulgarian Grigor Dimitrov, the 'spider cam' that hovers above court stopped right in the players' eyeline, preventing them from serving, the BBC reported.

Russia's Andreeva served out victor...