“Symbolically we have equal treatment but in reality not yet,” the 33-year-old told Monday’s edition of the Augsburger Allgemeinen paper.

Outside the four grand slams, the women have fewer tournaments than the men and less prize money, former top 10 player Petkovic said.

“That means the women’s WTA Tour is not equal to the men’s WTA Tour,” she said.

“We get the same prize money at the four biggest tournaments of the year, the grand slams – and that is always hung on us as a flaw.

“Because 90 per cent of people see tennis only in connection with the grand slams and then think: the men play a maximum of five sets, so up to five hours, the women’s three at most – that’s unfair,” she explained.

But the crux of the matter for the players is the women’s tour outside the Australian Open, French Open, Wimbledon and US Open is “90 per cent of the year.”