US Open - Stosur out to prove US Open win was no fluke
The unpredictable Stosur played the match of her life to defeat Williams on the tenth anniversary of the September 11 attacks on the United States.
But she rejected suggestions she would be dismissed as a one-Slam wonder without a successful title defence at Flushing Meadows.
"Even if I don't win the tournament, I don't think it was a fluke anyway," Stosur said. "Of course you want to come back and do just as well as the year before.
"I have been trying hard and training well and I'm really looking forward to this year's tournament. You don't come back to defend a Grand Slam every year or every tournament, so it's good. It's exciting."
The final Grand Slam of the year begins on Monday and Stosur is seeded seventh. She begins her campaign against Croatia's 21-year-old Petra Martic, ranked 65th in the world.
The 28-year-old Stosur admitted after rousing victories at Wimbledon and the Olympics that Serena deserves to be favoured as the last one standing.
"Serena is probably the favourite coming in given her recent form," Stosur said. "No matter who you are, I don't think you can really deny that.
"It is what it is. It's fine whether you're talked of being the favourite or not. It doesn't really matter.
"Everyone is starting from scratch at the moment and obviously things become clearer as the weeks go on."
Stosur has failed to convert her maiden major triumph into further glory at the Slams.
She lost in the first round of the Australian Open and the second round at Wimbledon. Her initially impressive run at the French Open ended with a thud when she was beaten by Italian Sara Errani in the semi-finals.
"Of course I wish I would've done better," Stosur said. "But everything goes the way it goes for whatever reason.
"Hopefully it's just a matter of time before it really starts happening again. You just have to put it together at the right time."
Stosur said her 6-2 6-3 upset of Williams last year was unforgettable.
"Given the court we were on, the stage, the final at the US Open against Serena, 9/11, all those things combined for one of the best matches I have played," she said.
"Other matches come to mind where you feel like you could not miss a ball. You kind of think, 'Oh, am I going to wake up from this and things will kind of become normal again?'
"I don't think I had one of those days, but I am very proud of the way I did play."
Stosur had her first training session inside Arthur Ashe Stadium on Thursday and the memories flooded back.
"That was really nice to walk back out onto that court," she said. "Little things pop into your mind as you're walking out there again.
"Probably the forehand winner I hit on match point. That was the one thing that came back first."
Stosur said she revelled in playing outside Australia because of reduced expectations.
"Melbourne, you go out for breakfast and you see yourself on the front page or back page of the newspaper," she said. "I don't see that here."
She said seven different champions from the last seven majors shows the depth of women's tennis.
"We have had a lot of winners over the last couple of years but I think it's not because the competition is lacking or anything like that," she said.
"We're just in this period of time where there's not one dominant standout player. It doesn't mean everyone is rubbish."