Explained: The "We have 1028 days left" t-shirt message on the protestor who interrupted Casper Ruud and Marin Cilic's French Open semifinal clash

Friday's French Open men's semifinal clash between Casper Ruud and Marin Cilic was halted for 15 minutes after an environmental activist entered the court and chained herself to the net.

The incident took place during the third set when Ruud was leading Cilic 3-6, 6-4, 4-1. Both players were escorted to the locker room while security stepped in to resolve the issue.

French organisation Dernière Rénovation claimed responsibility for the protest, and said Alizée, the 22-year-old protester, had entered the court "to draw attention to the climate emergency."

"22-year-old Alizée stepped onto the tennis court during the Ruud-Cilic semi-final to draw attention to the climate emergency and the demand for the Last Renovation campaign," the tweet read.

In a statement issued on the group's website, Alizee said she interrupted the proceedings on Court Philippe-Chatrier because she could "no longer take the risk of doing nothing in the face of the climate emergency."

“We are in 2022 and it is time to face reality, the world to which politicians are sending us is a world to which Roland Garros will no longer be able to exist. Today, I entered the field because I can no longer take the risk of doing nothing in the face of the climate emergency,” Alizee’s statement read.

Alizee was wearing a white t-shirt with a message that read "We have 1028 days left". It is believed that this message was a reference to one of the UN's recent climate reports.

The group’s website also carried an explanation of the message with an updated countdown.

"1026 days is what we have left to determine the future of humanity. Less than three years. The countdown began on March 28, 2022, the end of the ultimatum sent by Last Renovation to the government, and the date on which citizens entered into civil resistance. France has been condemned by its own courts for climate inaction. The future of this country is literally destroyed. To waste time is to perish," the post read.

The activist interrupted the semifinal between Casper Ruud and Marin Cilic during the third set.

The French Open has had its share of interruptions in the past as well, notably during the 2009 final between Roger Federer and Robin Soderling, and in the 2013 title clash between Rafael Nadal and David Ferrer.

Rafael Nadal into his 14th French Open final, to face Casper Ruud on Sunday

Rafael Nadal advanced to the final after Alexander Zverev injured himself and retired during the second set.

Rafael Nadal booked his place in the 2022 Roland Garros final after World No. 3 Alexander Zverev suffered an unfortunate injury and was forced to retire from their semifinal clash. Sunday’s summit clash will mark a record 14th appearance in the final in Paris for the Spaniard.

Standing in the Spaniard's path is Casper Ruud, who became the first Norwegian to reach a Grand Slam final after his 3-6, 6-4, 6-2, 6-2 defeat of Marin Cilic.

This will be the first meeting between Nadal and Ruud, who trains in the Spaniard's academy in Mallorca.