On a ho-hum afternoon devoid of any truly significant surprises, Stephens reached the round of 16 in New York for the first time by beating 23rd-seeded Jamie Hampton 6-1, 6-3 Friday.
Williams, seeking her fifth U.S. Open title, was scheduled to face 78th-ranked Yaroslava Shvedova of Kazakhstan at night, after things came alive a bit thanks to 2001 champion Lleyton Hewitt's stirring 6-4, 5-7, 3-6, 7-6 (2), 6-1 comeback victory over 2009 winner Juan Martin del Potro.
It was the ninth time in the past 10 years that two previous title winners faced each other in New York; Hewitt was a participant in three of those in the past, going 0-3.
The 32-year-old Australian, a former No. 1 now ranked 66th after a series of injuries, repeatedly scrambled along the baseline to come up with passing winners against the sixth-seeded del Potro.
"I don't know how many years I've got left in me. I keep getting asked the question," said Hewitt, who won Wimbledon in 2002. "I'm just pumped to get out on this court and try to put on a great show."
Earlier, two other U.S. Open winners, defending champion Andy Murray and top-seeded Novak Djokovic, experienced only brief lulls before staying on course for a possible showdown in the semifinals.
About 40 minutes into his match, Djokovic faced two set points, but he erased those thanks to errors by his opponent, and after adjusting to the swirling wind, wound up defeating 87th-ranked Benjamin Becker 7-6 (2), 6-2, 6-2. Murray dropped a set, yelled at himself after some awkward miscues, but finished well, taking the last five games of his 7-5, 6-1, 3-6, 6-1 victory over 81st-ranked Leonardo Mayer of Argentina.
The buzz already was building about Williams vs. Stephens, even before Williams faced Shvedova.
Williams is 32, seeded No. 1, and owns 16 major titles. Stephens is 20, seeded 15th, and already carrying the label of "Next Big Thing" in American tennis. Not only that, but Stephens surprisingly won their Australian Open quarterfinal in January, one of only four losses in 66 matches for Williams in 2013. Oh, and then there's this: Stephens found herself in a bit of a brouhaha this year over less-than-flattering comments she made to a reporter about Williams.
O Sloane Stephens reaches the round of 16 for the first time in her career with a 6-1, 6-3 win over Jamie Hampton.
• Lleyton Hewitt rallies for a 6-4, 5-7, 3-6, 7-6 (2), 6-1 win against 2009 champ Juan Martin del Potro.
O Saturday, 9 a.m.
Men's third round, women's fourth round, Ch. 2