Djokovic pulls out of French Open with knee injury

World number one Novak Djokovic has pulled out of the French Open ahead of his quarter-final match due to a knee injury.

The top seed and defending champion was scheduled to play Casper Ruud in the quarter-finals on Wednesday.

The Serb sustained the injury during his marathon fourth-round win over Francisco Cerundolo on Monday.

The withdrawal ended the Serb's quest for a record-extending 25th Grand Slam trophy and will result in him losing the world number one ranking to Italian Jannik Sinner later this month.

"Due to a torn medial meniscus in his right knee (discovered during an MRI scan), Djokovic, who was supposed to play Casper Ruud in the quarter-finals tomorrow, has been forced to withdraw from the Roland Garros tournament," organisers said.

Last year's runner-up Ruud will now advance to the semi-finals.

Djokovic said he had been carrying an injury for a couple of weeks and that the problem flared up when he slipped during his match against Cerundolo.