Aggressive Serena Williams inflicted another devastating defeat on Maria Sharapova, crushing the Russian 6-1, 6-1 to reach the quarterfinals of the Miami Masters.
The rout on Tuesday came less than two months after the American won the Australian Open title over Sharapova 6-1, 6-2.
Top seed teenager Sharapova is struggling on serve after facing her second straight opponent from the Williams family. She struck eight double-faults, while producing 13 in her previous win over Venus Williams.
Sharapova never earned a break point and lost her own serve five times.
Williams will next face off in a rerun of an Australian Open semi- final when she plays Czech eighth seed Nicole Vaidisova.
"She was playing tough in first few games," said Williams. "I was hitting a little crazy, not feeling the ball.
"But after that, I started hitting better."
Williams has now won her last three matches over two-time grand Slam champion Sharapova.
In the quarters, Russian ninth seed Anna Chakvetadze became the first into the semi-finals, powering back to defeat China's Li Na, the number 15, 4-6, 7-5, 6-2.
On the men's side, fighting Scot Andy Murray saved two match points in the second set as Frenchman Paul-Henri Mathieu lost his nerve in a 2-6, 7-5, 6-3 fourth-round defeat to the world number 12.
Murray, now 22-4 with one title on the season, made the trip into a Masters last eight for the second event in a row after Indian Wells this month.
After his heroics in the second set, which sent the tight contest into a third, Murray took control, eventually claiming the victory on his fourth match point, a backhand cross-court winner.
The 19-year-old fired ten aces, and overcame 43 unforced errors while striking 32 winners and breaking four times on nine chances.
He will aim for a second straight Masters semi-final against either Andy Murray or Spaniard David Ferrer, a match, which serves as a potential preview for next month's Davis Cup quarterfinal between the nations in North Carolina.