After a moment's silence she suddenly screamed out in pain, then shouted "help me", clutching her right leg.
A gut-wrenching scene unfolded on Court 17 at Wimbledon on Thursday as Bethanie Mattek-Sands injured her knee.
With her husband, Justin, by her side, Mattek-Sands was attended to by paramedics for around 20 minutes, before being sent to a hospital via ambulance. Her knee was in a very weird position.
"It was like something you see only in the movies", Cirstea said.
Mattek-Sands, 32, was forced to retire from the second-round match with the score 4-6, 7-6 (4), 0-0 (40-15).
She added: "She kept staying, Sorana help me, Sorana help me, Sorana help me".
"The kneecap, it was I think out a little bit. I wish I could have done more".
Mattek-Sands could be heard crying and screaming out for help even after the medical support arrived, with the crowd dispersing after it became clear the match was over.
In a statement, the All-England Club said: "The first response to Court 17 was within one minute, by a qualified ambulance technician".
It's an unfortunate turn for Mattek-Sands, who was looking to complete a calendar-year Grand Slam in doubles after capturing the Australian Open and the French Open titles already in 2017. "That's tennis, you know".
Pliskova was the runner-up at the US Open previous year and had reached at least the quarterfinals of her last three Grand Slam events.
Top-seeded Angelique Kerber also advanced to the third round, along with seventh-seeded Svetlana Kuznetsova, ninth-seeded Agnieszka Radwanska, 14th-seeded Garbine Muguruza and 24th-seeded CoCo Vandeweghe.