The match between the two young Americans will be quickly forgotten, with Stephens handling the occasion significantly better and racing to a 6-3 6-0 victory in 61 minutes.
But what followed was a tremendous display of sportsmanship from two women who grew up together and have positioned themselves as not just the future but the now of American tennis.
They shared a long embrace at the net and, after Stephens had celebrated with her team in the stands, she returned and sat next to Keys at the side of the court, the pair smiling and laughing.
“I should just retire now,” said Stephens. “I told Maddie I’m never going to top this.
“Maddie’s one of my best friends on tour and I wouldn’t have wanted to play anyone else.
“I told her I wished it could have been a draw. If it was the other way round, I know she would have done the same for me.”
Keys admitted the nerves had got to her and she fought back tears as she said: “Sloane is truly one of my favourite people. To play her was really special. If there’s someone I had to lose to today, I’m glad it’s her.”
Given the bond between the two, it was no surprise that Stephens invited Keys to her celebrations or that her friend accepted – on one condition.
“She can buy me drinks, all of the drinks,” said Keys with a smile. “I’m really sad for me, but I’m so happy for her. I think drinks will help me through this tough time.”
At her moment of victory, 24-year-old Stephens turned to her supporters with a look of complete astonishment on her face, and no wonder.
In January a nagging foot injury forced her to undergo surgery and left her unable to walk for 16 weeks.
She returned at Wimbledon two months ago and lost in the first round, her ranking slumping to 957. Stephens then lost in the first round in Washington. “Eventually, I will beat someone,” she said. Fifteen wins out of 17 matches later, she walked off Arthur Ashe Stadium as tennis’ newest grand slam champion and 3.7m US dollars (£2.8m) richer.
She said: “It was just like, ‘Wow, how insane? I actually won the US Open’.
“There are no words to describe how I got here, the process it took or anything like that, because if you told someone this story, they’d be, like, ‘That’s insane’.
“I think it was just the joy of being able to get on the court again and compete, and then being able to compete at a high level. I think I went from just super excited to be on the court to super excited I was playing well to super excited I just won the US Open.”
Stephens was endearingly over-excited about every aspect of the presentation ceremony, especially when the value of her prize money was announced.
“What? Oh my God,” said Stephens, with Keys chipping in: “I’ll hold it for her.”
So has this given her the hunger to win more slam titles?
“Of course, girl,” she replied to her questioner. “Did you see that cheque that lady handed me? Man, if that doesn’t make you want to play tennis, I don’t know what will.”
At 83 in the rankings, Stephens is the fifth lowest-ranked woman to win a slam title in the Open era and her ranking will now soar to 17.
Keys, too, has had injury problems and the pair exchanged text messages, commiserating each other during the Australian Open as they sat at home.
The 22-year-old had her second wrist operation of the year after the French Open and, like Stephens, put her great form in New York down to an ability to play freely.
But that deserted her in a one-sided final.