Nadal and Federer both cruised through their third round US Open matches on Saturday in straight-sets and while David Ferrer, Milos Raonic, Richard Gasquet, Janko Tipsarevic, Philipp Kohlschreiber and Tommy Robredo had to do it a little tougher, they advanced as well.
A cranky John Isner along and Feliciano Lopez were the most notable players knocked out of the men's draw in the third round in Saturday's action.
World No. 2 Nadal can return to the No. 1 spot if he wins his second US Open title this year and on Saturday, he beat Croatian Ivan Dodig 6-4, 6-3, 6-3 to advance to the fourth round.
Dodig did put up a fight but was only able to create two break point opportunities against Nadal's serve all match and failed to convert both. However, the Spaniard took his chances winning 4-of-7 break points in the most pivotal factor in his straight-sets victory.
It sets up a tricky fourth round clash for Nadal, though, up against the gritty German Kohlschreiber.
The 29-year-old 22nd-seed is undergoing somewhat of a career renaissance over the past 18 months following a difficult injury run, and Kohlschreiber advanced to his fifth Round 4 appearance in his last eight Grand Slam appearances.
His improved form spurred on by being fully fit started by making the fourth round at the Australian Open in 2012 and last year, he also made the US Open fourth round and Wimbledon quarter-final.
This year he again made the French Open fourth round and is now into the round of 16 again. Prior to 2012, he had only managed that three times since making his ATP Tour debut in 2002.
Kohlschreiber won his third round match-up against American giant Isner 6-4, 3-6, 7-5, 7-6 (5) after the 13th-seeded big man was still cranky after his home crowd somewhat turned against him in the previous round against enigmatic Frenchman Gael Monfils.
Federer might have slipped down to No. 7 in the world coming into his 14th US Open, but the 32-year-old remains a definite contender for a sixth title at Flushing Meadows after a crushing 6-3, 6-0, 6-2 third round victory on Saturday night over Frenchman Adrian Mannarino.
The Swiss' thumping win sets up a fourth round meeting with Spanish veteran Tommy Robredo, who beat Brit David Evans 7-6 (6), 6-1, 4-6, 7-5.
Evans was the man who beat Australia's Bernard Tomic in the second round and Japan's 11th-seed Kei Nishikori in the first round so it was an impressive win from the 31-year-old Spaniard.
However, Federer leads their head-to-head battles 10-0 beginning way back at Sydney in 2002 and most recently at the 2011 Australian Open, so will be heavily favoured in the battle of the 30-plus year-olds.
Spanish world No. 4 Ferrer had a tough four sets up against Kazak Mikhail Kukushkin, but eventually prevailed 6-4, 6-3, 4-6, 6-4 in a match where precious little separated the two players besides Ferrer's experience in the finish.
Ferrer will now take on Serb 18th-seed Tipsarevic in the fourth round after he advanced by beating talented American Jack Sock, 3-6, 7-6 (1), 6-1, 6-2.
Big-hitting Canadian Raonic also had a tough four-set battle with the 22nd-seeded Spaniard Lopez, but got over the line after dropping the first set in a tie-break, 6-7 (4), 6-4, 6-3, 6-4.
Raonic's win sets up a mouth-watering fourth round battle with eight-seeded Frenchman Gasquet who also had a tough time against Russian Dmitry Tursunov, before the 32nd-seed retired through injury. Gasquet in the end won 6-3, 2-6, 6-4, 4-2.
A massive Day 7 of men's action now awaits as well beginning on Arthur Ashe Stadium with defending champion Andy Murray taking on talented German Florian Mayer. The night clash on Arthur Ashe sees world No. 1 Novak Djokovic take on Portugal's Joao Sousa.
Louis Armstrong Stadium hosts an exciting match-up first-up between Stanislas Wawrinka and Marcos Baghdatis and then latter German No. 12 seed Tommy Haas up against Russian 21st-seed Mikhail Youzhny.
Three intriguing matches are then on the Grandstand court beginning with Frenchman Julien Benneteau up against Czech Tomas Berdych before Australia's Lleyton Hewitt battles Russian Evgeny Donskoy, and finally American Tim Smyczek faces Spaniard Marcel Granollers.
Out on Court 17, there could be another fascinating third round battle also beaten Italian Andreas Seppi and Uzbekistan's Denis Istomin.