Madrid, Spain: Holder Petra Kvitova blunted a late attack from France's Kristina Mladenovic to advance 6-3, 7-6 (7/5) into the third round of the Madrid Open on Monday.
The Czech second seed, chasing a fourth title on the Caja Magica clay, has now won her last five matches over qualifier Mladenovic in straight sets.
Sloane Stephens beat former world number one Victoria Azarenka 6-4, 2-6, 6-2 to equal her best showing at the event, defeating the two-time Australian Open winner for the fourth consecutive time.
Belarusian Azarenka committed nine double-faults in going down to the American eighth seed.
"I was taking control from the baseline points, I was doing the right things," Azarenka said.
"I was playing smart tennis. But I didn't create anything with my serve today and it was really frustrating.
"I didn't really have a game plan, that's something I need to take a look at and fix.
"I need to make it more simple and just do the right things."
Former US Open winner Stephens also reached the third round here in 2014 and 2018.
Dutch seventh seed Kiki Bertens advanced past 2017 Roland Garros champion Jelena Ostapenko 6-4, 6-3.
Last year's losing Madrid finalist Bertens hammered 11 aces as she went through in 80 minutes, breaking Ostapenko four times.
In the men's first round at the ATP-WTA pre-Roland Garros tune-up, Russian 11th seed Karen Khachanov ended a five-match losing streak as he put out Spain's Jaume Munar 6-4, 6-7 (5/7), 6-3.
Khachanov earned his last win in mid-March at Indian Wells.
Germany's Philipp Kohlschreiber defeated Mikhail Kukushkin 6-2, 7-6 (7/5), while Frances Tiafoe beat Georgia's Nikolaz Basilashvili 6-7 (8/10), 6-3, 6-4.