Top seed Rafael Nadal booked his place in the US Open quarter-finals with a business-like victory over fellow Spaniard Feliciano Lopez at Flushing Meadows.
Nadal broke Lopez, ranked 23rd for the tournament, once in each of the three sets to record a 6-3 6-4 6-4 victory that showed him at his most professional rather than dominant.
The 24-year-old was quickly into his stride, breaking at the first attempt as he notched the first three games of the match.
Lopez did manage to halt the procession but Nadal was looking strong and even managed to defend four break points on his way to a 6-3 first-set win.
The Wimbledon champion was forced to work hard at the start of the second set, which followed serve for four games until Lopez capitulated with a weak third service game.
That offered Nadal a chance to seal the set, provided he could defend his own serve, and with Lopez looking functional rather than inspired he did so, serving to love to clinch a 2-0 advantage.
Lopez continued to work hard but he simply did not have the firepower to dent his illustrious countryman's serve.
"I think I am playing well, but I am not playing yet at my highest level," Nadal said after the win.
"I am playing better and better every day and I had to play a little bit better this match."
"To be in quarter-finals of the US Open without losing a set and without losing a serve, two things must work really well: the concentration and the serve."
The world number one will meet Fernando Verdasco in the last eight after he came back from two sets down in another all-Spanish match-up against David Ferrer.
Eighth seed Verdasco was staring down the barrel of a fourth-round exit after losing the first two sets, but he mounted a stunning comeback to take the next three, wrapping up the match 5-7 6-7 (8-10) 6-3 6-3 7-6 (7-4) in four hours and 23 minutes.
After a time-out to treat an ankle injury, Verdasco began cranking up his famed forehand to change the complexion of the match.
Nevertheless, he still found himself a break down in the fifth set, and 4-1 down in the deciding tie-breaker before rallying to take it 7-4.
On match point Verdasco hit an incredible winner around the net post after scrambling to meet a sublime drop shot from No.10 seed Ferrer, before collapsing on his back near the net.
After the match an exhausted Verdasco, an Australian Open semi-finalist last year, saluted the crowd and planted a kiss on the Louis Armstrong Stadium court.
The 26-year-old will now face either top-seed Rafael Nadal or Feliciano Lopez in an all-Spanish quarter-final.
In other results, Mikhail Youzhny also progressed to the quarter-finals with a four-set win over Tommy Robredo on Wednesday.
The 12th seed - a semi-finalist at Flushing Meadows in 2006 - took out one of the six Spaniards in the Round of 16, winning 7-5 6-2 4-6 6-4.
The Russian's half-century of winners was tainted by 40 unforced errors in the win and he also was wasteful when it came to break-point conversions, winning four out of a possible 12.
Robredo produced just three break-point opportunities and could only convert one, which took him to the third set.
Youzhny will meet Switzerland's Stanislas Wawrinka in the quarters after the 25th seed knocked out American Sam Querrey in a marathon five-setter