Czech Petra Kvitova struggled with unforced errors but still had enough weapons to defeat American Jessica Pegula 6-4 6-3 on Friday to advance to the fourth round of the U.S. Open.
The two-times Wimbledon champion had 28 unforced errors and five double faults but moved up a gear when it mattered to win her first career meeting with baseline battler Pegula.
Sixth seed Kvitova broke the world No. 63 twice in each set and completed the win when Pegula sent a return wide.
Next up for Kvitova will be another American in Shelby Rogers, who earlier advanced with a 6-2 6-4 win against compatriot Madison Brengle.
The U.S. Open is the only Grand Slam event where Kvitova has failed to reach the semi-finals.