I'm willing to concede that Serena Williams is better than Steffi, Martina, Chris and Monica. But that doesn't mean I can't see that Serena is beatable at 34, and that she is mostly winning these days because no one has the mental fortitude to finish her off. Kudos to Karolina Pliskova for following Roberta Vinci, Angelique Kerber and Garbine Muguruza in not only outplaying the (former) world number one, but then holding her nerve long enough to actually win the match. By reaching three Grand Slam finals in one year, Kerber has proven herself to be the first real contender since Justine Henin -- 10 long years ago. Here's hoping for a competitive final, although the women's game has already come out a winner no matter the outcome.