Williams, who won the Wimbledon title on her last two visits in 2015 and 2016, is now on an 18-match winning streak at the All England Club.
Having missed Wimbledon last year while she prepared to have her first child in September, Serena is in pole position to win her first Grand Slam crown since becoming a mother.
The 36-year-old faces Italian world number 52 Camila Giorgi on Tuesday for a place in the semi-finals.
Asked if it was a flawless display, Serena admitted she is never satisfied.
“I’m a perfectionist. I always find something wrong,” she said.
“It was an interesting match. She was hitting the ball well. That’s why she got this far.
“It was a good win but it was tougher than the scoreline to be honest.”
The 90th Wimbledon win of her career — the most among active female players — means Serena, currently 181st in the WTA rankings, will return to the top 100 next week.
Williams had made a tentative return to action following complications during daughter Olympia’s birth, struggling in her few appearances before pulling out midway through the recent French Open with a pectoral injury.
But her blistering form and a series of shock results have paved the way for another Williams coronation at Wimbledon.
Garbine Muguruza, Maria Sharapova, Simona Halep, Petra Kvitova, Venus Williams, Caroline Wozniacki and Sloane Stephens have all been eliminated already.
It is the first time in Wimbledon history not one of the top 10 women’s seeds have reached the quarter-finals.
Serena, seeded 25th, was facing a fellow mother in Rodina, the world number 120 who calls the American her “idol”.
And it was child’s play on Centre Court for Williams, who hit 30 winners and served 10 aces.
Twenty years after making her Wimbledon debut, Williams looks as good as ever and she moves into the quarter-finals without dropping a set in her first four matches.
Serena needs to win three more matches to earn the 24th Grand Slam singles title of her career, a mark which would tie current record holder Margaret Court.