Roger Federer [Images] should concentrate on his own career rather than criticising others, Serb Jelena Jankovic [Images] said on Tuesday after being irked by the Swiss master's unflattering verdict on her number one world ranking last year.

Last month, former world number one Federer hit out at the way the WTA rankings were calculated, saying a player who has never won a Grand Slam should not be granted the number one spot.

Jankovic reached the top spot in the WTA rankings in August having never won a major tournament. She lost her first Grand Slam final to American Serena Williams [Images] at last year's US Open [Images].

The Serb has since dropped down to third in the world following a shock fourth-round defeat to France's [Images] Marion Bartoli [Images] at the Australian Open [Images].

"To be honest, I do not like to talk about players, I really prefer to focus on myself," Jankovic told Reuters in an interview at the Paris Open.

She said she could not understand why Federer felt the need to hit out at women's tennis while his great rival Rafael Nadal [Images], who took over from the Swiss as world number one, was so "humble".

"Why should he even care? I don't like putting my nose in other's business.

"I mean, one thing I like about Nadal is that he is such a great champion, he is so humble, always has kind words for everybody, he is a role model for everybody," said Jankovic.

"Federer is a great champion, I don't want to get in a fight with him but why does he care, I really don't understand. Why does he need to do that?"

Federer also led the charge against Jankovic's compatriot Novak Djokovic [Images] when he quit because of the heat in his Australian Open quarter-final match against Andy Roddick [Images].

"I'm almost in favour of saying, you know what, if you're not fit enough, just get out of here," the Swiss said.

Jankovic said Federer should not criticise fellow players. "I don't think it's nice to attack other players.

"If he retired, he probably had his reasons, he knows better. You cannot attack someone when you don't have proof, when you don't have a piece of evidence.

"There is no reason to offend him that way."

Jankovic will open her Paris Open campaign with a first-round match against Italian Francesca Schiavone.

The interview was organised by WTA Tour sponsors Sony Ericsson.

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