On paper, the China Open is a lopsided event. While it’s one of the WTA’s big four Premier Mandatory draws, it’s only a mid-level tournament for the men—though a highly lucrative one, of course. Yet Beijing still has the co-ed charm of a dual-gender event. Bringing the men and women together one last time adds a little fun to what can sometimes feel like a mercenary march through the fall season. And with both of the races for the year-end No. 1 ranking very much alive, there’s still something to play for.

Maybe that’s why Beijing has brought us a stellar lineup of semifinals in 2017. Here’s a look ahead at all four of them. If you’re in the States, these should be worth setting the alarm, or at least the DVR, for.

Simona Halep vs. Jelena Ostapenko

The Romanian and the Latvian have met just once, but it was a doozy: This year’s French Open final, which Ostapenko won after trailing by a set and nearly two breaks. Despite being devastated by the defeat, Halep has rallied since, and with new co-coach Andrei Pavel she has played some of her most purposeful tennis of 2017 in Beijing. Halep has already exacted revenge for one Slam defeat this week, against Maria Sharapova. Can she do it again? Much will depend, of course, on Ostapenko’s accuracy, but Halep will likely be determined not to leave it all up to her again. Winner: Halep

Alexander Zverev vs. Nick Kyrgios

Mirror, mirror on the wall, who’s the best Next Genner of them all? The 22-year-old Aussie seemed to have that title locked up this spring, when he beat Novak Djokovic twice in a row. But by August the 20-year-old German had one-upped him with a win over Roger Federer in the Montreal final, and had passed him in the rankings. Zverev still leads in the rankings, No. 4 to No. 20, but Kyrgios still leads their head-to-head 2-1. Is Zverev really the better player? How much does Kyrgios care about staying in front of his younger rival? We’ll find out in this intriguing contest. Winner: Zverev

Rafael Nadal vs. Grigor Dimitrov

On the minus side for Dimitrov, he trails his head to head with Nadal 1-8. Can there be a plus side to that situation? If the Bulgarian is thinking positively, yes—his lone win over Rafa came at this tournament last year, and in their most recent meeting, in the Australian Open semis, he pushed Nadal to five sets in one of the year’s classic matches. While this is just a semifinal at a 500, it still feels like a big test for both of these guys. Nadal is trying to add to his lead in the race for the year-end No. 1 ranking, and also keep his hard-court momentum going as 2018, and another trip to Australia, approaches—it’s never a sure thing how he’s going to play on this surface. As for Dimitrov, this is a chance to try to close the year the way he began it. Winner: Dimitrov

Petra Kvitova vs. Caroline Garcia

The other women’s semi is a rematch; this one is a test of form. Garcia and Kvitova are both playing some of their best tennis of 2017 at the moment. The Frenchwoman won the biggest title of her career last week in Wuhan, while Kvitova has been looking more and more ominous with each round in Beijing, where she has yet to drop a set. Looking at the two of them and their relative shot-making power, you might think Kvitova would dominate Garcia. But she only leads their head to head 3-2. While she did dominate in their last meeting, at the US Open, Garcia won the two prior matches. Winner: Kvitova