Kerber 'done with practice' after progressing at Indian Wells
The 36-year-old with three Grand Slam titles, who welcomed the birth of daughter Liana last year, defeated the 17th-seeded Russian 6-4, 7-5.
"It was a really intense match -- almost two hours for two sets," said the German. "It's another important win for me and gives me confidence for the next rounds.
"I was feeling good," Kerber added. "Hitting the balls good, moving good. I'm on the way to playing again good tennis against the best players."
Kerber said that she prefers playing tournaments instead of spending long hours on the practice court.
"I've practised now for months -- I'm done with practice," she said. "I'm happy to be having matches now.
"If you go out on the practice court every single day and do the same things, it's nice to be now in the tournament.
"We had three, four months of practice, preparation. It was a long time, so that's why I'm happy having tournaments now."
Kerber's victory set up a showdown with fellow WTA tennis mother Caroline Wozniacki, who booked her spot in the last 16 by defeating American Katie Volynets 6-2, 4-6, 6-0.
The pair of former number ones last met in 2019.
"We are friends now and we will be still friends after a match," Kerber said. "We will try of course to win.
"But at the end, I think there are more important things than a tennis match. For the crowd it will be an interesting match," she said.