New York: World No. 1 Carlos Alcaraz aced his first real test at the US Open on Saturday powering past Britain's Daniel Evans while women's second seed Aryna Sabalenka schooled France's Clara Burel to move into the fourth round of the year's final Grand Slam.
There were also lessons learned about grit under the Arthur Ashe Stadium lights as fifth seeded Tunisian Ons Jabeur gutted out a 5-7, 7-6(5), 6-3 win over Czech Marie Bouzkova.
Battling respiratory issues, Jabeur had complained she felt like a zombie during her first two matches but came back from the dead in a late night three-hour thriller to fend off Bouzkova, who also showed she is made of tough stuff playing with a heavily strapped groin.
Third seed Daniil Medvedev once again worked the US Open graveyard shift, beating in-form Sebastian Baez 6-2, 6-2, 7-6(6) to end the Argentine's 12 match winning streak.
It was the second consecutive match Medvedev started one day and finished it the next, having gone four sets with Australian Christopher O'Connell in a late night battle on Thursday that wrapped early Friday morning.
While not quite yet back to his best, Alcaraz's form and confidence have been building with each match as he bids to become the first man to defend his US Open title since Roger Federer won five straight from 2004 to 2008.
Against the 26th seeded Evans the 20-year-old Spaniard mixed moments of brilliance with lapses in focus but was never really threatened on his way to 6-2, 6-3, 4-6, 6-3 win.
Alcaraz's victory contributed to a brutal day for the British contingent with only young gun Jack Draper preventing a third round wipeout with a 6-4, 6-2, 3-6, 6-3 win over American wild card Michael Mmoh.
Draper arrived in New York unsure if he could compete after suffering a small tear in his shoulder that forced him out of the Winston-Salem tune-up event but on Saturday the 21-year-old was the last Briton standing.
Top seeded Briton, No. 16 Cameron Norrie, was dumped out 6-3, 6-4, 6-3 by Italian Matteo Arnaldi while American Peyton Stearns pushed the last British woman Katie Boulter to the exit with a 6-4, 6-3 victory.
In contrast to the British woes it was another bright day for the home fans as third seed Jessica Pegula led another American push into the last 16, stopping Ukraine's Elina Svitolina 6-4, 4-6, 6-2.
Joining Pegula were 2017 finalist Madison Keys, a 5-7, 6-2, 6-2 winner over 14th seed Liudmila Samsonova, Stearns and sixth seed Coco Gauff, who booked her spot on Friday with a win over Elise Mertens.
With four American men and the same number of women reaching the fourth round, home fans can dream of a Flushing Meadows trophy sweep no matter how far fetched that idea might seem.
Not since 2002 when Pete Sampras and Serena Williams were crowned US Open champions have Americans hoisted both trophies but with Pegula, Coco Gauff, Taylor Fritz and Frances Tiafoe all top 10 seeds and in the last 16, the chance will be there.
With Tommy Paul and Ben Shelton also advancing there will four American men in the fourth at the US Open for the first time since 2011.
The last time Flushing Meadows had a chance to celebrate a homegrown women's champion was in 2017 when Sloane Stephens beat Keys in an all-American final while the men's title drought extends back two decades to Andy Roddick's victory in 2003.
In other action sixth seed Jannik Sinner took down 2017 US Open champion Stan Wawrinka 6-3, 2-6, 6-4, 6-2 to set up an intriguing fourth round meeting with 12th seeded German Alexander Zverev, who was a 6-7(2), 7-6(8), 6-1, 6-1 winner over Bulgarian Grigor Dimitrov.
