NEW YORK (AFP) - Defending champion Emma Raducanu shrugged off fears about her US Open fitness after breaking down in tears during a practice session at Flushing Meadows on Friday (Aug 26).

The British teenager needed to be consoled by coach Dmitry Tursunov during Friday's practice as she appeared to tearfully complain about a problem with her right hand.

However, speaking to reporters later, the 19-year-old brushed off the incident, insisting she had "no concerns" ahead of Monday's opening round.

"I think that today, the practice, I had, like, a few small things, got a couple of blisters, a bit of a niggle here and there," Raducanu said.

"It's just one of those weird days where you feel a bit like nothing... I don't know. You just feel a bit out of it.

"Can't really explain myself, to be honest. I'm sure everyone in this room has probably had a day like that. It is what it is."

Pressed further about her fitness, she replied: "I mean, I have no concerns of, like, an issue, no."

Raducanu, who has had repeated problems with blisters this season, made tennis history last year after becoming the first qualifier in the Open era to win a Grand Slam singles title.

The 11th seed, who opens the defence of her title on Tuesday against French veteran Alize Cornet, said she felt no additional pressure as reigning champion.

"I think you guys are thinking probably more about pressure and ranking than me," she told reporters.

"I think defending a title is just something that the press makes up. I'm just taking it one match at a time. Like, every single player is very capable in this draw. I just focus on what I'm doing, my own trajectory. As I said last year, I'm just going to do things my way."