Serena Williams is ready to handle the pressure of going for the calendar Grand Slam after going through a similar experience at Wimbledon.
The American, 34, won her fourth straight major title, dubbed a 'Serena Slam', at the All England Club in July.
Williams now has the chance for her first calendar Slam of all four majors in a year if she wins the US Open.
"I think Wimbledon gave me unbelievable practice for this," said the world number one in New York.
"At Wimbledon I was going for the second Serena Slam. That is rare.
"So that really gave me the best practice and preparation in terms of going for the Grand Slam."
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Who has done it before?
Steffi Graf was the last player to win the calendar Slam in 1988, and the only other women to do so were Margaret Court in 1970 and Maureen Connolly in 1953.
Williams has been breaking records ever since she won her first major title at Flushing Meadows in 1999 - another victory this year and she would become the first woman or man in the open era to win the US Open seven times.
She would also draw level with Graf on 22 Grand Slam singles titles, two behind all-time leader Court.
'I have always dreamt of winning the Slam'
Asked if she now believes she is the greatest player ever, Williams said: "I can't sit here and say that.
"I can sit here and say that I'm the greatest player that I've been able to be. I do read numbers and I do see numbers. I believe in those numbers."
Williams, who faces Russia's world number 86 Vitalia Diatchenko in round one, is the three-time defending champion at Flushing Meadows.
She said that winning the US Open had always been as much of an ambition as a calendar Slam.
"I always dreamt of winning the US Open," she said. "I have always dreamt of winning the Grand Slam. It was just a dream.
"I never thought I would be close to doing something like that. My dream originally was always to win here in New York."