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.
Kvitova took the opening set on a break and started the second set with another, But Mladenovic broke back for 3-all and eventually forced the contest to a tiebreaker, which Kvitova captured.
"I had to fight, but I'm glad that I had this (kind of) match. Hopefully, it's given me a bit more freedom for the next round," last month's Stuttgart clay winner said.
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. An indifferent season continued for 2017 ATP Finals champion Grigor Dimitrov, with the Bulgarian falling to Taylor Fritz 7-6 (10/8), 7-6 (7/4). Fritz will take on world number one Novak Djokovic in the next round. 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.
A French pair advanced in opening matches with Richard Gasquet, playing for the first time since October due to injury, beating Spanish youngster Alejandro Davidovich Fokina, last weekend's Estoril semifinalist, 7-5, 7-6 (7/5).
Gael Monfils, the 15th seed, continued an injury comeback, taking out Italy's Andreas Seppi 6-3, 6-1.
Marin Cilic saved four match points to beat Slovakia's Martin Klizan 6-4, 2-6, 7-6(0).
The Croatian had lost his previous four matches but triumphed in two hours 48 minutes to set up a meeting with Jan-Lennard Struff.