Melbourne, Jan 5: Defending champion Serena Williams on Friday said she will withdraw from the Australian Open, adding she was not fully prepared to keep playing after becoming a mother four months ago. "My coach and team always said 'only go to tournaments when you are prepared to go all the way'," Xinhua news agency quoted Williams as saying. "I can compete -- but I don't want to just compete, I want to do far better than that and to do so I will need a little more time," she added. In January last year, Serena won the Australian Open for an Open-Era record seventh time, defeating her sister Venus. This was her 23rd Grand Slam singles title, surpassing Steffi Graf's Open Era record of 22. "The memory of last year's Open is one that I will carry with me, and Olympia and I look forward to coming back again. I appreciate the support and understanding of my fans and everyone at the Australian Open," said the 36-year-old. The 23-time Grand Slam winner played her first match since giving birth at the World Tennis Championship in Abu Dhabi on December 30, losing her exhibition match to reigning French Open Champion Jelena Ostapenko. "After competing in Abu Dhabi, I realized that although I am super close, I'm not where I personally want to be. With that being said, and even though I am disappointed about it, I've decided not to compete in the Australian Open this year," she said.