The last time they met in a major was the final of the 2017 Australian Open, which Serena won while playing two months pregnant.
After an even start to the second set Serena found an extra gear to win three games on the spin, including two further breaks of serve, to thrill the NY crowd and book an expected night session match-up with Venus, seeded 16th, on Friday.
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.
In other action, Sloane Stephens made it through after being taken to three sets by Anhelina Kalinina of Ukraine, the defending champion eventually winning 4-6, 7-5, 6-2.
"It's obviously a tough match", Serena added.More news: Mixed feelings for Leon Balogun after Brighton and Hove defeat to Liverpool
"You're beating it up now", the elder sister said.
"The last time we played the Australian it was two against one so at least this time it will be fair". "Any other questions about anything else?"
"If I would say my true feelings, it would be bleeped out, because it was ridiculous", said Azarenka.
"Definitely I'm going to watch this match". "That love-40 game at four all was not looking good and you guys really got me through that".
The USTA admitted they were wrong to hand Cornet a warning for slipping off her shirt on court after realizing she had put the garment on back-to-front during a heat-break. "My designs are inspired by strong, sexy, sophisticated, sassy, sure, smart, stylish, silly, and spontaneous women who are living their best lives, or making it up as they go-kinda like me". Nadal won 46 of 55 first-serve points and wore down Vasek Pospisil, 6-3, 6-4, 6-2, in Ashe Stadium.