"My goal is to try and win the US Open," the Belgian said at Flushing Meadows on Saturday, two days before the opening of the year's final Grand Slam tournament.
"I've trained hard. I'm in maybe the best shape that I have been in. I'm not worried physically that I'm not ready to do it."
At the age of 29 and having announced her impending retirement several months ago, Clijsters has been on a farewell tour this year, though injuries have restricted her to six tournaments.
When she made her comeback after her first retirement, in 2009, Clijsters won the US Open before going on to win a third Flushing Meadows title in 2010 and the Australian Open title in 2011.
Clijsters will be playing in all three events in New York, including the mixed doubles with America's Bob Bryan but is not worried about the effects on her body.
"My mindset is not any different," she said. "I haven't played many matches or many tournaments. I really believe that physically I can do it."
A quarter-finalist at the Olympics, Clijsters said she hopes to feed off the atmosphere of a venue where she has been successful three times before.
"Obviously this place is magical for me," she said. "I have had so many beautiful memories.
"I love the surface, I love the atmosphere, and I'm excited. I'm not really thinking about retiring yet. I'm still focusing on trying to be in the best shape that I can be.
"When I start Monday I want to be playing well so I'm focusing on that for now. I'll be as ready as I can't be and not look too far ahead. I'm focused on just trying to play my best."
Having quit once to get married and have a daughter and with plans to expand her family in the future, Clijsters said there would be no second comeback this time, not even were she to win the title again.
Clijsters said the timing is right for her to retire.
"You know in here," she said, tapping her heart.