Former world number one Martina Hingis has conceded she has no hope of surviving on the women's circuit unless she improves her serve and increases her all-round power.
Swiss Hingis, 25, who retired three years ago with foot and ankle injuries, announced her comeback to tennis this month.
"If I want to play the tennis I played three years ago I would not survive," Hingis told reporters on Queensland's Gold Coast on Friday. "I know that. You have to grow with the game and you have to get better physically and tennis wise.
"I've been trying to work on my whole game, baseline and serve. You have to have a serve to be able to survive today and we'll see if I can bring it on, like the saying says."
Hingis will be making her Grand Slam return at next month's Australian Open after playing warm-up tournaments on the Gold Coast next week and in Sydney the week after.
The five-times Grand Slam champion said she had no goals other than to compete at the elite level although she added she would not have made a comeback if she did not think she could win more Grand Slam titles.
"You have to believe that down deep otherwise I wouldn't come back. I don't want to set myself into a kind of frame where I would be disappointed or reach over the top," she said.
Hingis said she was inspired to come back for a variety of reasons, including watching Lindsay Davenport's rise to world number one and the revival of Mary Pierce, who made the finals of the French and US Opens this year.
"I've had a very nice quiet life back home without the stress and travel but I miss playing. I miss the game," she said. "I'd wake up in the morning and sometimes I'd have no reason to wake up and that's what I was missing.
"I'm taking a risk but I'm willing to take it. I love the challenge and if I can survive, great, but if not it's not a drama. There's worse things that can happen to me."
