'Parents, never give up on your kids. If they want to do something, always encourage them,' the champion says
Stephens, who was ranked 957th only five weeks ago, but rose to 83rd, beat her American contemporary No.15-seeded Keys with 6-3 and 6-0 sets to claim the first grand slam title of her career.
Having foot surgery Jan. 23, Stephens said "If someone would told me then that I would win U.S. Open, I would have said it was impossible."
"I should retire now ... I will never be able to top this," the 24-year-old added.
Stephens won the top prize of $3.7 million for becoming the champion, and thanked her mom.
"Parents, never give up on your kids. If they want to do something, always encourage them," she said.
After winning the title, Stephens sat with Keys on the sidelines of the Arthur Ashe court. The two finalists have been close friends for many years.
"Sloan was very supportive," Keys said. "If there was someone I had to lose today, it was her," she added.