British number one Heather Watson has said that a combination of stress and tension contributed to her exit in the first round of the US Open.

The 23-year-old crashed out of the tournament following a 7-6[3] 7-6[0] defeat to Lauren Davis, leaving her still waiting for a first win at Flushing Meadows.

"I was thinking a lot about this match, thinking that it was a big opportunity, and thinking about the previous years and my results here," Watson told Sky Sports News.

"So I think that maybe I thought about that maybe a bit too much. I was cramping a little bit in my hand, and then when I moved to the other side of the court I started cramping in my legs.

"I'm fit coming into the tournament. It's not that I'm not fit. I think it was just a mix of the tension and a bit of the stress and everything together."

Watson has never made it beyond the third round of a Grand Slam tournament.