Pennetta, at 33 the oldest first-time Grand Slam finalist in the Open era, on Saturday became the first Italian to win the US Open women's crown with an efficient 7-6 (4), 6-2 victory over compatriot and childhood friend Roberta Vinci.
Dane starting to hit top form after up-and-down season and breakup
Grand Slam king Roger Federer came back with renewed vigor after a weather delay to rout Spaniard Marcel Granollers 4-6, 6-1, 6-1, 6-1 and charge into the fourth round of the US Open on Sunday.
Caroline Wozniacki trusts her stamina so much that she plans to return to New York in two months to run a marathon.
With mentor Martina Hingis cheering from the stands, 17-year-old Belinda Bencic became the youngest US Open quarterfinalist since Hingis herself in 1997.
No 39 ranked Peng Shuai stunned 14th-seeded Czech Lucie Safarova in straight sets to reach a personal milestone and keep China's hope alive.
Fifth seed Milos Raonic claimed the throne as King of the Tiebreaks, blasting his way into the fourth round of the US Open with a 7-6 (5), 7-6 (5), 7-6 (3) win over Victor Estrella Burgos on Saturday.
Once again, John Isner's trip to Flushing Meadows ended in the third round. Once again, it happened with a loss to Germany's Philipp Kohlschreiber at that stage.
Instead of trying to match Wimbledon champion Petra Kvitova's power, unknown Aleksandra Krunic confounded her with looping shots and frustrated her by chasing down every ball.
Denmark's Caroline Wozniacki beat the heat and Maria Sharapova 6-4 2-6 6-2 to move into the quarter-finals of the U.S. Open on Sunday as another top seed disappeared under a broiling Flushing Meadows sun.
Wimbledon champion Petra Kvitova was stunned in the third round of the US Open by a scrambling, moon-balling qualifier ranked No 145.
Peng Shuai beat 28th-seeded Italian Roberta Vinci 6-4, 6-3 at the US Open to reach her second straight Grand Slam round of 16.
Williams taking nothing for granted despite emphatic second-round win