The second round of the Western and Southern Open was completed with more surprising results. Third seed Serena Williams survived against Arantxa Rus while fourth seed Naomi Osaka and eighth seed Johanna Konta were also among those moving on.
Sixth seed Petra Kvitova fell to countrywoman Marie Bouzkova and seventh seed and defending champion Madison Keys was swept aside by Ons Jabeur.
Serena overcomes Rus challenge
Williams was tested throughout the over three-hour contest, saving a break point in the fourth game of the first set and a set point in the tiebreaker before pulling it out 8-6.
Rus claimed two straight breaks in the second set to go ahead 3-1 and she closed it out 6-3. The final set looked to be in Williams' control as she led 5-2 only to see the Dutchwoman produce a stunning fightback, winning four games on the trot.
Serving for the match, Rus was broken and Williams proceeded to shut out the world number 72 in the final set tiebreaker.
"Now I feel like I have passed that test, and now I can pass the test at the (US) Open at (Arthur) Ashe Stadium", she said. "At one point I was pumping my fist saying come on!' I had a crowd in my head. It was actually funny to me. For me, it was like there was a crowd there."
Osaka, Sabalenka come through three-set battles
Osaka dropped the opening set against Karolina Muchova before recovering for a 6-7 (5), 6-4, 6-2 victory. After trading early breaks to begin the match, the set went to a tiebreaker and Muchova went up 3-0, saw Osaka rally to level at 4-4 and won the set when the fourth seed sent a groundstroke long.
Osaka broke in the second game of the second set and made the advantage stand up, firing an ace on set point to square the match at a set all. The two-time major champion went up 5-1 in the deciding set and her 12th ace sealed a hard-fought win.
"I think the difference [between winning and losing] was probably attitude", she said. "In the second set I felt more at peace with myself. I realized there are certain balls I needed to go for.
"I feel like I just learned a lot throughout the entire course of the match, and hopefully it's something I can do at a quicker rate."
Sabalenka fought from a set down to defeat Catherine Bellis 6-7 (1), 6-4, 7-5 striking 28 winners in the victory to advance to the third round.
"[Bellis] played really well", she commented. "I tried my best, and she put me under pressure, and I was just trying to handle it.
"I knew it was going to be tough and I am proud of myself that I was able to handle all of these emotions going through, and to finally win this match."
Kvitova, defending champion Keys sent packing
In an-all Czech battle, it was Bouzkova who sprung a surprise against Kvitova on Court 17, triumphing 2-6, 7-5, 6-2 in two hours, 25 minutes.
After being blitzed for a set and a half, the 22-year old rattled off nine of the last 11 games of the match, converting on all four of her break point opportunities.
Keys was never in her match against Jabeur with the Tunisian running out an easy 6-4, 6-1 winner on just 59 minutes as the American committed 29 unforced errors.
"It was a really good match for me. I had to serve really good and I played really good", she said afterwards. "I didn't give her the chance to get her rhythm back. I know it was very difficult as a first match back for her.
"To be honest, I'm very, very proud of the way I played today."
Konta, Kontaveit, Mertens, Yastremska among other winners
Eighth seed Konta blasted Kirsten Flipkens 6-2, 6-0 and will next face qualifier Vera Zvonareva, who also lost only two games in a 6-1, 6-1 thrashing of Laura Siegemund.
12th seed Anett Kontaveit continued her fine post-lockdown form with a solid 6-3, 6-3 win over Jil Teichmann and will next be challenged by Bouzkova while 14th seed Elise Mertens slipped past Kristina Mladenovic 6-1, 6-7 (5), 6-3.
13th seed Maria Sakkari recorded a 6-4, 6-3 win over Yulia Putintseva while 16th seed Dayana Yastremska needed three sets to see off Bernarda Pera 7-6 (5), 4-6, 6-3 and will meet Osaka next while Victoria Azarenka scored a 6-2, 7-6 win over Caroline Garcia.
Christina McHale was victorious over Ekaterina Alexandrova 6-1, 7-6 (8) and will square off with Jabeur next while Jessica Pegula is Sabalenka's next opponent after a 7-5, 6-2 win over Amanda Anisimova.