PRAGUE, Czech Republic — Former world No. 1 Karolina Pliskova says she's parted with coach David Kotyza.

Pliskova hired Kotyza, the former coach of her fellow Czech Petra Kvitova, in December.

With Kotyza, Pliskova won three WTA tournaments. She reached the semifinals at the French Open and lost in the quarterfinals of the U.S. Open to lose her No. 1 ranking.

In a message to local media on Friday, the fourth-ranked Pliskova says she and the coach failed to agree on "the strategy of my further development."

It is not immediately clear who will replace Kotyza.