MELBOURNE (Reuters) – Serena Williams brushed off concerns about her fitness on Saturday and declared herself “at 130 percent” for her Australian Open title defence.

The 21-times grand slam singles champion has played almost no competitive tennis since the U.S. Open last September and pulled out of the Hopman Cup two weeks ago with knee inflammation.

Pictures of the 34-year-old taking a time-out during training circulated on social media on Saturday, raising concerns she might not be fit to take on Camila Giorgi in the first round at Melbourne Park on Monday or Tuesday.

Williams, though, said the knee inflammation was no longer a problem — “it’s actually really fine” — and any issues she had on the practice courts were simply the result of her heavy training workload.

“I’m a little tired today. I’ve been working so hard and doing so much work, so … maybe I had a bad attitude out there,” the world number one and top seed told reporters.

“I’m at 120, 130 percent right now … I actually wanted to have an easy day today. But to me in my mind ‘easy’ is just two hours of really intense working out.”

Williams said she would be relying on her vast experience to make up for her lack of time on court ahead of her 16th Australian Open, six of which she has won.

“I didn’t have the match play that I’ve wanted to have,” she said. “But after playing for so many years on tour, I should be able to focus on that and the fact that I have played a lot of matches.”

A shock defeat to Italy’s Roberta Vinci in the semi-finals of last year’s U.S. Open denied Williams the chance of a single season grand slam after she had won the Australian and French Opens as well as Wimbledon.

Williams said she was neither prepared to discuss that missed chance nor would she contemplate her chances of achieving the rare feat this year.

“I don’t think about it, I never thought about it really,” she said. “It was in front of me last year but it still wasn’t there, so …”

Williams also brushed off any thoughts that she might be suffering more from nerves this year because of her lack of on-court action over the last four months.

“I don’t have anything to prove,” she said. “I have nothing to lose. I can only gain. That’s kind of how I look at it right now.”

(Writing by Nick Mulvenney in Sydney, editing by Peter Rutherford)