Serena Williams enjoyed a one-sided victory over her older sister Venus, although there will be concerns over her fitness after she survived an early injury scare.
The 36-year-old met her sister for the 30th time on Saturday night, with this encounter coming more than 20 years after their first.
It was a strange sight to see the pair meet so early in Grand Slams – indeed, only their first meeting in the second round of the Australian Open in 1998 came earlier than this – but 38-year-old Venus was some way short of matching her younger sister on the night.
While she was able to exert her dominance in a 6-1 6-2 win over the seven-time major winner, Serenas hopes of winning a seventh US Open and a record-equalling 24th Grand Slam title must hang in the balance after an awkward fall early in the match.
Her ankle was heavily strapped and recovery will be key ahead of her fourth-round tie with Estonias Kaia Kanepi.
On her way to court, Serena admitted she felt honoured to be a part of the historic match-up.
Its amazing how Venus and I have been able to continue to play after so many years, she said. I feel honoured to be part of this amazing duel.
But while only Chris Evert and Martina Navratilova (22) have met more times than the Williams sisters (16) in majors, this was not one of their most competitive battles. In truth, it left a lot to be desired.
After a fast start, where the 23-time Grand Slam champion held with ease and set up break points, disaster nearly struck for Serena as she was wrong footed by her sister and appeared to roll her ankle.
The break point chances passed and Venus held, before Serena required treatment at the changeover after just three games.
Despite the heavy taping she received on her right foot – it was a wonder that she was able to get her shoe back on – Serena struck once they returned to court, moving 3-1 up.
A second break soon followed as Serena asserted her dominance over her older sibling, winning her fourth game in a row since receiving medical treatment and wrapping up the first set.
An early break saw Serena assume control of the second set and while Venus ended a seven-game losing streak with a brave hold, the damage was done.
Another break – this time to love – followed and Serena stormed into the last-16.