However, despite her impressive triumph and surge up the world rankings she suffered first-round defeats at the Wuhan Open and the China Open in Beijing before pulling out of the Hong Kong Open earlier this month.
Stephens, who will play her first round-robin event at this week's Elite Trophy, blamed her recent defeats on a lack of preparation.
"I'd say winning the U.S. Open isn't the best preparation to go play two tournaments right after," she told a news conference on Monday.
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"But I had to get out there and play because it was on my schedule. Before winning the U.S. Open, having those good results, I was basically trying to get into the Australian Open. These tournaments were really necessary for me to play."
Stephens, seeded third, is placed at the top of the Camellia Group alongside Latvian Anastasija Sevastova and Barbora Strycova of Czech Republic.
Angelique Kerber, who clinched both Australian and U.S. Open titles last year, said the Elite Trophy will allow her to lay a foundation for a fresh start in 2018.
"I'm trying to look ahead and trying to end the year as well as I can by putting everything on the court," said the 29-year-old German.
"It's a tough tournament but it's an opportunity to get better, have good competition and maybe also going with a good feeling to next season."
Kerber was drawn in the Rose Group alongside fourth seed Russian Anastasia Pavlyuchenkova and Ashleigh Barty of Australia.
The Elite Trophy features the world's top 12 singles players who did not qualify for the WTA Finals last week. The round-robin format will see the winners from each of the four groups advance to the semi-finals.
(Reporting by Hardik Vyas in Bengaluru; Editing by Christian Radnedge)
