Sharapova is currently ranked 62 as she battles back from injury
Maria Sharapova thrashed fifth seed and world number 10 Nadia Petrova to reach the quarter-finals of the Bank of the West Classic in California.
The three-time Grand Slam champion is continuing her comeback, having returned in May after nine months out because of shoulder surgery last year.
And the 22-year-old Russian hammered compatriot Petrova 6-1 6-2 in Stanford.
There were also wins for third seed Elena Dementieva, Daniela Hantuchova and Samantha Stosur.
Dementieva swept past fellow Russian Maria Kirilenko 6-1 6-2, the unseeded Hantuchova upset seventh seed Agnieszka Radwanska of Poland 4-6 7-6 (8-6) 6-1, and Australian Stosur beat Monica Niculescu of Romania 6-1 7-5.
Sharapova, ranked 62nd, was playing just her 17th match since returning from injury and enjoyed her second win in that time over Petrova, having also won their second-round encounter at the French Open.
"I knew what I had to improve upon," said Sharapova, who beat Japan's Ai Sugiyama in the first round in Stanford. "I started that first match lousy. This time the goal was to get a better start.
"I was aggressive the whole way through. I didn't have many letdowns and even when I made unforced errors I stayed with it."
Sharapova will next play the winner of the match between Venus Williams and Alla Kudryavtseva of Russia, and the former world number one would relish the chance to face Williams.
"Its always great to come back and play someone who's at the top of the game and playing pretty well. I always relish playing the top players," she said. "I'd love to play against her."