Tennis pioneer Billie Jean-King waded into the French Open scheduling row on Saturday by claiming women players are treated like “second-class citizens”.

Roland Garros organisers came under fire for putting nine men’s matches in 10 night sessions this year. “You’ve got to put them when it’s prime time, and you have got to figure it out and you want to give equal opportunity to both genders,” said US legend King, a founder of the WTA and vocal advocate for women’s rights.