Three to See: Time for the women's semifinals; Plus, Cilic vs. Edmund

Before each day's play at the Australian Open, we'll preview and predict three must-see matches.

What can stop Wozniacki now? The No. 2 seed has bounced back from 1-5 down in the third to win a match, and the experience appears to have made her stronger. Since then, she has played top-level tennis to knock off Magdalena Rybarikova, and resilient tennis to fend off Carla Suarez Navarro. Wozniacki seems to believe that her first major title is finally, truly within her grasp. But while the 22-year-old Mertens is ranked just 36th, and has nothing like Wozniacki’s pedigree as a former No. 1, the 5’10” Belgian is riding a wave of fresh momentum. She has also been playing a game—crisp, forceful, forward-moving—that would seem to be tailor-made to beat the Dane’s steady-as-she-goes style. Wozniacki won their only meeting, in three sets, on clay last year. It’s tempting to predict that Mertens will turn that result around on Thursday and ride her momentous wave all the way to the final. But I can’t quite bring myself to do it. Winner: Wozniacki

The No. 1 seed and the 2016 Australian Open champ have reached their respective peaks in Melbourne. On Wednesday, Kerber was virtually flawless in her 51-minute dismantling of Madison Keys, while Halep bounced back from an 0-3 deficit in the first set against Karolina Pliskova and dropped just two more games. Now the questions are: Whose peak is higher? And has either woman peaked too soon? Judging by their head-to-head and career records, the answer to the first question would appear to be Kerber. She and Halep have played eight times since 2014, and Kerber has won five, including the last two, which were both on hard courts. If she falls behind, Halep will have the advantage of having already extricated herself from a near-death experience against Lauren Davis. But Kerber will have her own story of survival to recall; she nearly went out to Su-Wei Hsieh over the weekend. The only thing we know for sure is that this match should be fought tooth and nail, to the bitter end. With their form being equally fine at the moment, I’ll take Kerber’s peak over Halep’s. Winner: Kerber

Like Cilic vs. Sam Querrey at Wimbledon and Kevin Anderson vs. Pablo Carreño Busta at the US Open, this is the Grand Slam semifinal that no one saw coming. By now, we should expect bigger things from Cilic, who hit 83 winners to beat a hobbled Rafael Nadal in the quarterfinals. The Croat has a 1-0 record over his opponent, a 23-year-old Brit who had never been past the fourth round at a major before this week. Their semi will be a slugfest, and like Halep’s and Wozniacki’s on the women’s side, Edmund’s confidence and endurance will be boosted by winning two five-set matches earlier in the event. A few points may decide this one, but for now it seems more likely that Cilic will win them. Winner: Cilic

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