An annoyed Dinara Safina has had enough of people questioning whether she can justify being the world number one, despite not having won a grand slam title.

The Russian bristled at the Los Angeles Championships on Monday when asked about world number two Serena Williams' comments she was the people's number one as she holds the US., Australian Open and Wimbledon titles.

"I didn't do the ranking system," said Safina.

"If she has questions, she can give these questions to the WTA who is doing the ranking system.

"It's the result of how you play the whole year, not just the four grand slams. I've been playing the whole year and I've been having great results all through the grand slams."

Safina has won at Rome, Madrid and Portorotz and reached the Australian Open and the French Open finals, as well as the Wimbledon semi-finals this year.

However, she has been thrashed in all of those grand slam matches, to Serena at the Australian Open, to Svetlana Kuznetsova at Roland Garros and to Venus Williams at Wimbledon.

She was also beaten by Serbian Ana Ivanovic in the final of the French Open last year.

Her top ranking was also questioned by former world number one Jelena Jankovic, who also had similar criticisms levelled at her when she held the mantle as the top-ranked player.

"If I had to pick someone after me, I'd pick Serena," Jankovic told Reuters last week.

"To be number one, you should be complete and if you are number one you have to be beating the Williams sisters.

"I'm one of the rare players who has a positive record against the Williams sisters."

Safina, who is a combined 2-9 against the Williams sisters while Jankovic is 8-8, said the Serb's perception of what should define the number one ranking was ill conceived.

"The ranking system is not only based (on) if you beat Serena and Venus," she said.

"It's based on how you play the whole year.

"It has nothing to do with what your record is against them.

"Did she beat them in the final of a grand slam? No. It doesn't count when you beat them at a tier four (tournament)."

Safina has a 973-point lead in the rankings over Serena, and unless she has a complete meltdown in the events leading up the U.S. Open, the WTA said she would enter the year's final grand slam beginning on August 31 as the world number one.

The Russian added she was confident her first grand slam title was only a matter of time.

"I'm putting in 100 percent every day," Safina said.

"I'm practicing and if has to come it comes. I think it's just a matter of time and one day it will happen."