CINCINNATI, Ohio - World No.8 Karolina Pliskova has split with coach Tomas Krupa and will work with good friend and former doubles No.1 Rennae Stubbs. The Czech confirmed the news after scoring her first win ever over Agnieszka Radwanska in the first round of the Western & Southern Open. She was previously 0-7 vs. the Pole, having never won a set. 

"I just felt like I need to do some change," Pliskova said regarding her coaching decision. "I don't want to make changes when I just feel bad. I just felt I need somebody a little bit more positive."

"I feel like he's a little bit negative. I'm also negative and I'm always so hard on myself. I think he's the same. It's somehow not going together."

"It's sometimes not the mistake of the coach. I'm not saying he was bad."

"But sometimes it's just important to understand how the player feels, because [Rennae] was in the same situation. So for me, this is important. And also, it's a woman. So we have maybe different feelings than men sometimes."

Pliskova was ranked No.1 this time last year, but her 2018 results so far have left her frustrated. Down to No.8 in the rankings and at No.9 on the Porsche Race to Singapore, the 26-year-old hopes to kick-start her game with Stubbs by her side. The pair worked together for the first time last fall at the BNP Paribas WTA Finals Singapore presented by SC Global, where Pliskova made the semifinals for the first time in her career. 

"I really liked Rennae when we were working in Singapore last year," Pliskova said. "It was just about a few weeks' work, but it was so positive and she's just positive, doesn't matter how I play, how I feel. 

"For a couple of weeks she's going to try to help me out. She has her stuff, a lot to work around, not only me. I think this could work at least for a few weeks. For next year we'll see, but we have just a few tournaments to go this year, so I think I'm going to just stay with her."

"I have been around her for four days, so it's not much, but actually I feel positive, and, look, I beat Radwanska for the first time in my life," Pliskova said with a laugh. "I'm not saying it's because of her, but for sure I feel pretty good and I'm just happy on the court, which I didn't feel for a while.

"With me, I need to enjoy a little bit, and if I'm not enjoying, I'm not gonna play good tennis ever. So right now just enjoying, doesn't matter what the score was, so that's the most important thing for me."

Pliskova said Stubbs has helped simplify her game, while coaxing her to get herself to the net more often. A champion here in 2016 and a semifinalist last year, Pliskova hopes getting her head right will help her turn things around ahead of the US Open, where she was a finalist in 2016.

"Even though it's not the best season ever, things are not that bad. I'm still, what, [No.9] in the race, so it can be also worse.

"I felt like also the end of the year last year was not great for me, the tournaments in Asia. And with Rennae I felt just happy on the court, and also knowing that she just understand my game, which is also important. So she doesn't want any crazy things for my game. 

"She just understands me pretty well, what I feel, what I can play, what situation I can serve or whatever. So she just, I think, just suits me better than Tomas."