After losing to Ekaterina Makarova in the fourth round of the Australian Open, world No. 5 Angelique Kerber said she’s contending with a back injury.

“I could move; that was fine. But just my serve, when I go back, there is a lot of pain there,” said Kerber, who added that she will visit a doctor. “I actually feel it, like two, three days. So I was thinking it will be maybe not too bad, but in the first set I was feeling that and it was actually worse and worse. I take the treatment, but it was not too good.”