The French Open semi-final between Casper Ruud and Marin Cilic was held up for more than 10 minutes after a woman invaded the court and tied herself to the net.

The woman, believed to be a climate-change protester, wore a T-shirt bearing the slogan ‘we have 1028 days left’.

She walked on to Court Phillipe-Chatrier unchallenged during the third set and attached herself to the net, raising serious questions about security at Roland Garros.

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The protester halted play at the French Open (AP)

Tournament director Amelie Mauresmo looked on as the players left the court for 10 minutes while the woman was removed.

The incident came after Alexander Zverev suffered a serious injury in the first semi-final, forcing him to retire from his match against Rafael Nadal.

Tournament chiefs later said the protester, who had a valid ticket, had been handed over to the police.

A French Tennis Federation statement read: “At 9.12 pm, an environmental activist managed to get onto Philippe-Chatrier court and attached herself to the net with metal wires and glue.

“The security team needed to formally identify the objects she used to get onto the court before they could remove her.

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The activist was eventually removed (Christophe Ena/AP)

“The players were escorted to the changing rooms. The score was 3-6 6-4 4-1 to Casper Ruud against Marin Cilic.

“Play was suspended for 13 minutes, and resumed at 9.25 pm.

“The young woman, of French nationality, entered the grounds with a valid ticket early in the day.

“She was then handed over to the police.”

Norwegian Ruud went on the win the match in four sets to reach the final, where he will play 13-time winner Rafael Nadal.