Serena Williams beat her elder sister Venus in a Grand Slam match for the first time in six years to reach the Wimbledon quarter-finals.
The world number one came through 6-4 6-3 in one hour and eight minutes on Centre Court.
Serena, two years younger at 33, has now won 15 of the American siblings’ 26 professional contests.
She remains on course to complete the third leg of a possible calendar Grand Slam.
Her last defeat at one of the four majors came at the All England Club 12 months ago, and her sister could not end a run that has taken in victories at the US, Australian and French Opens.
“It’s never easy to play someone you love and care about,” said the world number one. “You just play for the competition and enjoy the moment.”
Illness and injury have hampered Venus since her last Wimbledon victory in 2008, but with five Wimbledon singles titles apiece, the fourth round was still an early stage for such a heavyweight encounter.
“It definitely doesn’t get any easier,” Serena said after their sixth Wimbledon meeting.