Grand slam champions Garbine Muguruza and Maria Sharapova booked their spots in the US Open last 16, while Venus Williams capped a special day for her family.
Wimbledon winner and Spanish third seed Muguruza stormed into the next round with a straight-sets win over Magdalena Rybarikova at Flushing Meadows on Friday.
Sharapova - a five-time major champion - battled past American teenager Sofia Kenin during the night session in New York.
Veteran Venus also progressed to the round of 16 after sister Serena Williams had her first baby.
MUGURUZA STAYS HOT
Favourite to win the year's last slam, Muguruza accounted for Rybarikova 6-1 6-1.
Muguruza is yet to drop a set at the US Open after easing past the player she beat by the same scoreline in the semi-finals of Wimbledon.
Her 61-minute victory earned a showdown with two-time Wimbledon champion and 13th seed Petra Kvitova.
Kvitova won the battle of the seeds, defeating Caroline Garcia 6-0 6-4.
The Czech advanced to the fourth round of a slam for the first time since recovering from a horrific knife attack in December.
-- US Open Tennis (@usopen) September 1, 2017
SHARAPOVA MARCHES ON
Kenin put up a fight but the experience of former world number one Sharapova paid off in a 7-5 6-2 victory on Arthur Ashe.
Playing her first grand slam since the 2016 Australian Open, having tested positive for a banned substance at Melbourne Park last year, Sharapova was challenged but passed the test.
Next up for Sharapova is 16th seed Anastasija Sevastova, who beat Donna Vekic 6-2 6-3.
VENUS WINS AS SERENA WELCOMES BABY
It was a day to remember for two-time US Open champion Venus and Serena.
Venus reached the fourth round with a 6-3 6-4 victory over Maria Sakkari.
That was after 23-time grand slam champion Serena, 35, gave birth to a baby girl on Friday.
"Obviously I'm super excited," Venus told ESPN pre-match. "Words can't describe."
Carla Suarez Navarro awaits in the last 16, where Sloane Stephens and Julia Goerges will also feature.