Sloane Stephens was planning to spend Saturday night in New York celebrating with Madison Keys, hours after beating her friend to a first Grand Slam title.

The 24-year-old American ranked 83rd until Monday, thrashed 15th seed Keys 6-3 6-0 in just 61 minutes to complete a scarcely believable return from injury.

Asked if she would be buying the drinks, Stephens confirmed: "Yes, a lot of them apparently. We are having a little celebration and she is coming."

Just 69 days after returning from an 11-month injury layoff, and six weeks since her ranking dropped to 957, Stephens became only the fifth unseeded woman to win a Grand Slam singles title in the Open era.

And she later revealed it was boredom as much as nerves that threatened to upset her equilibrium during the 48 hours between semi-final and final at Flushing Meadows.

"I was literally in my room twiddling my thumbs,' she said. "I was looking at car reviews last night on Auto Trader, like literally. That's how bored I was. I didn't have anything to do."

Stephens admitted that the nerves finally took hold as she stepped out onto Arthur Ashe Stadium - but a little over an hour later her eyes were bulging as a cheque for $3.7m (£2.8m) was handed to her and she was announced as a Grand Slam champion.

She said: "There are no words to describe how I got here because if you told someone this story they'd be, like, 'that's insane'."