Madison Keys lamented her nervousness after being crushed by Sloane Stephens in the US Open final on Saturday.

Stephens needed just 61 minutes to claim a 6-3 6-0 victory over Keys in a clash between two Americans in their first grand slam final.

Keys, 22, rued her inability to handle the occasion of a major decider on Arthur Ashe Stadium, after committing 30 unforced errors.

"I think at the end of a slam, whoever is still on the court is physically going to be feeling something," she told a news conference.

"I definitely think my play came down to nerves and all of that, and I just don't think I handled the occasion perfectly."

Keys needed treatment on her leg during a semi-final win over Coco Vandeweghe on Thursday.

The runner-up said she was impacted by the injury, but she paid tribute to Stephens.

"I don't think I was moving perfectly, but at the same time, I'm not going to take anything away from Sloane. I think she played really well," Keys said.

"I don't think I played great. I think that's kind of a combination for a disaster for me.

"I'm obviously not happy with how things went out there, but I still fought as hard as I could and I did everything that I could and came up short."