Serena Williams enjoyed an overdue taste of victory as she beat Karolina Pliskova in her opening match at the Bank of the West Classic in Stanford on Wednesday night.

After suffering early exits in both the French Open and Wimbledon, Williams – winner of this tournament in 2011 and 2012 – found her rhythm with some big hitting to take a 10th victory in a row on these courts, advancing to the third round.

The world number one served nine aces while converting all three of her break point chances.

“I was playing a player I knew was going to be very difficult to break, so it was really important for me to be super focused on my serve today,” Williams told the WTA website.

“I’m still taking it a match at a time though – I’m just worried about doing what I want to do and what I’ve been practising on the court. But I wasn’t feeling any nerves today. I felt good. And I felt fine physically.”

But while Williams progressed, second seed Agnieszka Radwanska suffered an early exit as she was knocked out by Varvara Lepchenko.

Last year’s runner-up at the Stanford Classic and Wimbledon finalist in 2012, world number five Radwanska went one set down before fighting back to take the second against her American opponent – ranked 49th in the world – before the Pole dropped back in the third to lose 3-6 6-3 4-6 in a match lasting over two-and-a-half hours.

American qualifier Sachia Vickery also caused an upset as she dispatched Monica Puig with a comeback victory to progress to the quarter-finals.

The 19-year-old world number 197 lost the first set to her Puerto Rico opponent, ranked 69, before fighting back to claim a 6-7 6-2 6-1 victory in just over two hours.

Eighth seed Andrea Petkovic eased to a 6-2 6-2 win over Naomi Osaka.