The British No1 twice stopped her session with Russian Ekaterina Alexandrova at Flushing Meadows on Friday.
Raducanu had her right wrist taped and appeared in discomfort before sobbing and being consoled by coach Dmitry Tursunov.
After composing herself, Raducanu returned to the court and continued to pound forehands but shortly afterwards the session again stopped and the 11th seed headed off court with physio Will Herbert for approximately 15 minutes.
There was no further cause for alarm, with Raducanu completing the two-hour session, serving and playing points.
Addressing a press conference later on Friday, the 19-year-old said: “I had a few small things, got a couple of blisters, a bit of a niggle here and there. It’s just one of those weird days where you just feel a bit out of it.
“I can’t really explain myself, to be honest. I’m sure everyone in this room has probably had a day like that. I have no concerns of an issue, no.”
Raducanu will take on France’s Alize Cornet in the night session on Louis Armstrong Stadium on Tuesday as she looks to pick up where she left off in last year’s extraordinary run to the title.
It has been a whirlwind 12 months for the teenager, who has had to try to adjust to the demands of professional tennis in the full glare of the spotlight.
She faces plummeting down the rankings if she cannot make it to the latter stages of the tournament again but played down talk of pressure, saying: “I think you guys are thinking probably more about pressure and ranking than me.
“I think defending a title is just something that the press makes up. I’m just taking it one match at a time. 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.”
Raducanu’s record in 2022 stands at a modest 13 wins and 15 losses but she at least arrived in New York on the back of one of her best tournaments of the year in Cincinnati, when she defeated Serena Williams and Victoria Azarenka before losing a close contest with Jessica Pegula.
“It’s really nice to be back in New York,” said the 11th seed. “It’s great for me to come here having done a year on the tour, having played most of the tournaments.
“I’m really happy with what I’ve done this year and how I’ve come out of certain situations. I’ve obviously got amazing memories in New York.”
Taking her first steps back into Flushing Meadows, Raducanu’s mind returned to the drive from Manhattan to Queens last year ahead of her final clash with Leylah Fernandez.
“Obviously, the first thing that you see is when you get out the car here, walking into the gate,” she said.
“The last memory I have of it is before the final that morning, I felt so sick in the car here. I just blamed it on being car sick, but I think I was a bit nervous, too.
“The whole car journey, my head was in my hands. I was, like, ‘What’s going on’? As soon as I got out of the car, I just promised myself, ‘Look, you just fake it, do whatever you can’, and it worked well that day.”