Madison Keys produced a comeback to beat Angelique Kerber at the Cincinnati Masters, while world number one Simona Halep rolled on.
Keys lost the opening set but hit 55 winners to upstage Wimbledon champion and fourth seed Kerber on Thursday.
Rain wreaked havoc throughout the day just like it did for Halep on Wednesday, but the top seed returned to complete her victory against Australian qualifier Ajla Tomljanovic.
Two-time Wimbledon winner Petra Kvitova saw off Kristina Mladenovic, but US Open champion Sloane Stephens was sent packing by Elise Mertens.
KEYS RALLIES PAST KERBER
American 13th seed Keys survived to defeat Kerber 2-6 7-6 (7-3) 6-4.
Keys trailed 1-7 in her head-to-head record with Kerber but came from behind to book a quarter-final berth.
"Considering the last - what was it, six times? - it didn't go so hot, this victory feels good," Keys said. "More than anything, it was just how I handled being down and not letting the previous results kind of spiral in my head for me. I think that's what I'm happiest with."
Next up is in-form Aryna Sabalenka, who stunned sixth seed Caroline Garcia 6-4 3-6 7-5.
HALEP WAITING FOR BARTY CLASH
After overcoming Tomljanovic 4-6 6-3 6-3, French Open holder and Rogers Cup champion Halep set up a meeting with Ashleigh Barty.
But that clash was pushed back to Friday due to the rain in Cincinnati.
"It's a tough opponent. We played in Canada last week, so I expect a tough one. Hopefully, I will be at my highest level of tennis to win the match," Halep said of Barty.
STEPHENS SHOCKED BY MERTENS
World number three Stephens crashed to a 7-6 (10-8) 6-2 defeat against 15th seed Mertens.
Mertens – making her main-draw debut at the tournament – claimed five successive games in the second set as she went on to close out victory.
"It's really awesome to be able to play like this against a player like Sloane, who has a Grand Slam already," Mertens said afterward. "It gives you confidence."
Kvitova awaits Mertens after the eighth seed topped Mladenovic 6-4 6-2.
There were also wins for Lesia Tsurenko and Amanda Anisimova.
|Vidic hails Ronaldo as ultimate professional ahead of Old Trafford return|
|Warriors´ Cousins nearing NBA return|
|Pogba can´t do the basics – Souness criticises Man United star|
|Messi absence big blow for Barca as Icardi talks up Inter|
|´You can´t cry, that´s true´ – Ronaldo responds to Isco|
|Bartomeu: Barca still competitive without Messi|
|Bills RB McCoy remains in concussion protocol|
|Raiders place Marshawn Lynch on IR|
|Emery calm over title talk after another Arsenal win|
|Green: Warriors have to clean up defensively|
|Mariners say Bolt talks ongoing amid reports contract offer was rejected|
|Proud captain Ozil revels in Arsenal´s ´sexy football´|
|Puel angry over Holding handball|
|Cilic breezes through in Basel, Anderson fights back|
|Ingram: Four-game ban better than we expected|
|Raiders send Cooper to Cowboys for first-round pick|
|Arsenal 3 Leicester City 1: Outstanding Ozil inspires comeback win|
|World Series 2018: Three reasons why the Dodgers will win|
|Yarmolenko out for six months after Achilles surgery|
|World Series 2018: Three reasons why the Red Sox will win|
|Ozil eclipses Klinsmann to become Premier League´s most prolific German|
|Allegri expecting Old Trafford battle against Mourinho´s United|
|Bertens feared she did not belong in Kerber clash|
|Returning Ronaldo expecting ´tough´ game against Manchester United|
|Cristiano Ronaldo confident of clearing his name amid rape allegation|
|Osaka looking to learn from losing start in Singapore|
|Kovac expects tough test against AEK Athens|
|Whyte gives Chisora deadline over rematch|
|Spartak Moscow sack Massimo Carrera|
|Atletico Madrid confirm fresh injury issue for Gimenez|
|Dolberg extends Ajax contract after Real Madrid links|
|Ronaldo an example for Lukaku to follow|
|Bertens battles back to blast past Kerber|
|Ramos apologises for training ground fracas|
|Raikkonen should take heed of Alonso misfortune as F1 career winds down|
|Guardiola wants Manchester City fans to push team to Champions League glory|
|Isco not interested in departed Ronaldo - he didn´t want to be here|
|World Series 2018: Three storylines to watch in Red Sox-Dodgers|
|Neymar focus bad for football - PSG´s Maxwell|
|Marco Ianni charged by FA over Jose Mourinho touchline row|
|Stephens sees off Osaka in see-saw Singapore battle|
|I´m happy at Manchester United - Mourinho dismisses Real Madrid reports|
|Semenya and Asher-Smith head IAAF Female World Athlete of the Year shortlist|
|Mandzukic to miss Manchester United trip|
|I turned down Manchester United to return to Juventus - Bonucci|
|Sanchez out of Manchester United´s clash with Juventus|
|Australia make Short work of run chase in T20 win|
|Brotherly g-love! Tommy Fury follows Tyson into the pros|
|Ozil´s international retirement can help Arsenal - Emery|
|If you sack Lopetegui, you have to sack us all – Isco|
|Lopetegui defiant amid Real Madrid sack reports|
|Sri Lanka spinner Herath to retire after Galle Test|
|Ronaldo returns for Old Trafford welcome amid disquieting noise|
|Garcia claims third Andalucia Valderrama Masters title|
|Ex-England international Waldrom retires|
|´Massive personality´ Hart can lift Burnley, says Kompany|
|Liverpool felt wrath of ´emotional´ Klopp, says Shaqiri|
|Reid: Jenkins capitalised on Kaepernick movement|
|Manchester United v Juventus: Ronaldo out to end dismal scoring record against Mourinho|
|Injured Ribery to miss Bayern´s clash with AEK|
|Wilshere would have stayed at Arsenal under Wenger|
|Mahomes stars again as Chiefs crush Bengals|
|Bolt must accept ´much less´ to join Mariners, says A-League chief|
|Klopp compares Liverpool to dog without favourite toy|
|Young leads Hawks to first win, Thunder fall in Westbrook´s return|
|Spalletti hits out at physical Milan – I had three players asking to be replaced|
|Cowboys, Ravens lose after missed kicks in final seconds|
|Hernangomez secures Nuggets´ win over Warriors with last-second block|
|Hasler returns to Manly on three-year deal|
|Sarri: Chelsea fans must respect Mourinho|