On a column for BBC Karolina Pliskova recalled her first match on the WTA Tour against her sister Krystina earlier this year in Birmingham. Karolina wrote: "They didn't even watch on television back in the Czech Republic.
My mum doesn't usually like to watch our matches anyway because she is too nervous. My father usually does watch matches - but not this one. He did something else to take his mind away from it. So we both felt very nervous and didn't know what would happen - if we would play good tennis or bad tennis.
It was huge pressure for me because if you look at the rankings I should win easily. Of course I wanted to win the match, but I also didn't want my sister to lose. It was an emotional rollercoaster. We ended up playing a long match and Kristyna won 6-2 3-6 7-6 (9-7)!
It was the biggest victory of her career - she had never beaten a top-five player before that." Karolina has a close relationship with Krystina: "Of course we look similar because we are identical twins. However, I think we have aged a little differently, and we try to be different because we have never wanted to be the same.
We have different tattoos. She is a little more blonde. And our personalities are quite different. But sometimes we think in the same way, and we often say the same thing at the same time - that makes people laugh."