Karjus said that the new working relationship happened by chance.

"She [Tsurenko] was looking for a coach and we had a chat. I have known her from an early age, but not well. We talked a bit and here I am," Karjus said.

Tsurenko has won for WTA tournaments in her career to date, with a grand-slam career high of the quarter finals at the 2018 U.S. Open.

"I'm helping her prepare for next year and everything is going well at present," Karjus added. 

"Right now, general physical fitness and tennis are coming together, with the focus on tennis. Let's see what comes out of this...I'll go with her to China and Australia, and we'll see if our cooperation continues," Karjus added.

Tsurenko, 30, ranked 23rd early on this year, but slipped down the rankings to 72nd, primarily due to injury.

"I think if she does well next year, she can play some pretty quality tennis. She has dropped in the world rankings, but she suffered a lot of minor injuries in the second half of the year. At the moment, all the worries seem to be diminishing and everything else improving," he went on.

"This is a great challenge and a great responsibility for a coach. I am delighted that I have this opportunity and am trying to make the most of it, to help her as much as I can," Karjus continued.

Download the ERR News app for Android and iOS now and never miss an update!