Serena Williams overpowered German Carina Witthoeft 6-2 6-2 to set up a third round clash with big sister Venus at the US Open.
Williams sent down 13 aces and 30 winners on Thursday (NZ time) to record her second consecutive straight sets victory at Flushing Meadows as the 36-year-old, who is hunting a record-equalling 24th Grand Slam title, wrapped up the win in one hour and seven minutes.
"It's always such a great crowd at night. It's just amazing to play in front of this crowd," she said courtside after her victory.
"I was happy with a lot of things."
Next up is a 30th career meeting with Venus, who beat her younger sibling in their most recent encounter at Indian Wells earlier this year.
The last time the two sisters met at a Grand Slam was in the 2017 Australian Open final, where Serena prevailed in straight sets.
"It's obviously a tough match," Serena added.
"It's so young in the tournament, but it is what it is. It's not the end of the world. We would rather have met later. We're both going to come out per usual and play our best in front of you guys.
"Normally, I would say cheer for me. But, whoever you feeling -- me or Venus will work."
Two-time champion Venus beat Italy's Camila Giorgi 6-4 7-5.
Venus, seeded 16th, powered through the first set but appeared to lose energy toward the end of the second in broiling conditions inside the newly built Louis Armstrong Stadium.
She said the crowd's encouragement had helped her.
"I felt the energy, definitely," Venus said. "That love-40 game at four all was not looking good and you guys really got me through that."
Defending champion Sloane Stephens avoided an early exit, recovering from a set down to defeat Ukrainian qualifier Anhelina Kalinina 4-6 7-5 6-2.
Kalinina, 21, was the runner-up in the girls' singles in 2014 and was playing in her first senior grand slam tournament after coming through qualifying.
She took advantage of errors from Stephens to win the first set and then fought back from 4-1 down in the second set to level at 5-5 but the American held firm to win her ninth successive match at Flushing Meadows.
The third-seed fired an ace on match point to complete the comeback, which took two hours and 46 minutes on a hot and humid day on Arthur Ashe Stadium.
Meanwhile, Spanish 12th seed Garbine Muguruza succumbed to unseeded Karolina Muchova of the Czech Republic who recovered from a set down to win 3-6 6-4 6-4 to book a third round clash with Australian Ashleigh Barty.
Other seeded winners on the women's side included No. 8 Elina Svitolina, No.15 Elise Mertens, No 19 Anastasija Sevastova and No.23 Barbora Strycova, all in straight sets.