Russian second seed Ekaterina Alexandrova beat defending champion Linda Noskova 7-6(5), 4-6, 6-2 at the Monterrey Open on Thursday to secure her place in the semifinals of the US Open tune-up event.
Alexandrova, 14th in the world rankings, started the decider brightly after two tightly contested sets, and while Czech Noskova fought back to level at 2-2, the Russian regained control to seal victory in just over two hours at the WTA 500 event.
"I'm really glad that I could make it through, even in three sets, because it was difficult today — she served so well, she hit so hard from the baseline that sometimes there was nothing I could do," Alexandrova said.
Next up for Alexandrova is Czech Marie Bouzkova, who carved out a comfortable 6-3, 6-2 win over Croatian Antonia Ruzic.
Russian Diana Shnaider also progressed to the semis after fighting back from a set down and saving five match points against Elise Mertens to triumph 3-6, 7-6(6), 7-6(4) in a three-hour encounter with the Belgian fifth seed.
"Very happy, satisfied and proud to get the win today. I think the level of tennis was huge today," the third seed said.
World number 22 Shnaider next faces Alycia Parks after the American beat Slovak Rebecca Sramkova 6-2, 7-5.
Shnaider holds a 2-1 record against Parks, including a straight-sets victory at Indian Wells earlier this year.
"I've played her a couple of times — she's a great player. I keep telling myself to stay within myself and not really worry about my opponents."
The US Open runs from August 24 to September 7.