Serena Williams has declared that she is surprised by her current level of form after she reached her 35th Grand Slam quarter-final earlier today.

The five-time Australian Open winner thrashed Maria Kirilenko 6-2 6-0 in Melbourne in a match which saw her finish with a first-serve percentage of 87%.

Williams believes that she is playing her best tennis for some time and thinks that she has a good chance of extending her fine record at Melbourne Park.

She said: "I thought I played really well, I didnt expect to play so well, I was like 'wow'. I saw I served 95% in the first set, I was thinking 'Who is this girl? It's not me!'

"I've had a great career, especially here in Australia. Sloane Stephens is playing great, I think she has incredible talent. It will be a tough match but I feel like I have nothing to lose and am playing really well."

Williams goes up against teenager Stephens in an all-American quarter-final later this week.