|world number 1 Simona Halep (photo by Daniel Ward)|
Simona Halep (1) vs. Lesia Tsurenko
Madison Keys (13) vs. Aryna Sabalenka
Petra Kvitova (8) vs. Elise Mertens (15)
Elina Svitolina (5) vs. Kiki Bertens
Halep has now played eight straight matches since she began her title run in Montreal. There have been multiple rain delays and changes conditions. She did receive a medical timeout a couple of nights ago, but has shown no other signs of wear and tear. All the same, it's fair to wonder if--at some point--some type of fatigue will set in.
Win or lose, Tsurenko has had a good tournament, taking out both Ekaterina Makarova and the defending champion and world number 7, Garbine Muguruza.
Keys got her second win over Angie Kerber yesterday, and now faces another big hitter in Sabalenka. Sabalenka is on a roll in Cincinnati, where she has already shown the exit to Jo Konta, 2016 champion and 9th seed Karolina Pliskova and 6th seed Carolina Garcia, who held a match point in their third round contest. The Belarusian has had to go three sets in every round, which is never helpful to any player. On the other hand, she possesses healthy doses of both grit and confidence.
The cooler weather has been a boon to Kvitova, but the humidity, if it intensifies, could be a problem. Kvitova has never played Mertens before, which could create some discomfort. A lot of this will have to do with serving: Both players possess very good serves (though different kinds of serves), and both can be inconsistent with their serves.
Perhaps the most interesting of the four matches will be the one to be played by Svitolina and Bertens. They have played each other once, in 2016, on a hard court. It went to three sets, and Svitolina won. But this is a more aggressive, more confident Bertens than we saw two years ago. No longer a threat just on clay, the Dutchwoman is looking good on all surfaces. Speedy Svitolina, however, can given any player headaches on the right day.