US Open, Flushing Meadows
Dates: 30 August - 12 September Start time: 1600 BST
Coverage: Live text commentary on BBC Sport website and mobiles; updates on BBC Radio 5 live; live on Sky Sports
Nadal has made it into the last eight without dropping a set
Rafael Nadal gave further evidence that he is playing his best ever tennis in New York as he beat Feliciano Lopez to reach the US Open quarter-finals.
The world number one came through 6-3 6-4 6-4 in the night match on Arthur Ashe Stadium to set up a clash with another Spaniard, Fernando Verdasco.
There was greater drama elsewhere as both Verdasco and Stanislas Wawrinka won enthralling five-set matches.
Wawrinka's victory took him through to a quarter-final with Mikhail Youzhny.
The Swiss followed up his defeat of Andy Murray with a marathon 7-6 (11-9) 6-7 (5-7) 7-5 4-6 6-4 win over American Sam Querrey in four-and-a-half hours.
Wawrinka joins five-times champion Roger Federer in the last eight - the first time Switzerland has ever had two men in the quarter-finals of a Grand Slam.
The 25th seed took the first set on a tie-break against Querrey but was broken when serving for the second set as his opponent hit back to level the match.
Wawrinka then came from 3-1 down to win the third set but Querrey broke once to level again, before the Swiss broke in the 10th game of the decider to reach his first Grand Slam quarter-final.
"It's the first time for me, so for sure I am very happy with that," he said. "It's something very important, and I knew before the match it was going to be tough, but I was really focused on the match, on staying with him."
Russia's Youzhny, the 12th seed, beat Spaniard Tommy Robredo 7-5 6-2 4-6 6-4 to move within one victory of matching his 2006 run to the semi-finals.
"It's the first time in a year that I have already had two quarter-finals in Grand Slams," said the Roland Garros quarter-finalist. "It maybe means I'm starting to play a little bit more consistently. I hope to continue."
Verdasco outdid even Wawrinka with an incredible win over David Ferrer on Louis Armstrong Stadium as he recovered from two sets down, then a break down in the decider and finally 4-1 down in the final set tie-break.
The eighth seed eventually saw off his fellow Spaniard 5-7 6-7 (8-10) 6-3 6-3 7-6 (7-4), sealing victory with a spectacular winner on the run after four hours and 23 minutes.
"It was a very tough match and after losing the first two sets it was the best comeback of my career," said Verdasco.
After several lengthy ties, Nadal and Lopez did not begin their match on Arthur Ashe Stadium until after 11pm local time, but the world number one was in no mood to hang around.
I think I am playing well, but I am not playing yet at my highest level
He eased to victory in a little over two hours and has still to drop serve in the tournament, saving four break points against his countryman.
"To be in the 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," said Nadal.
"I think I am playing well, but I am not playing yet at my highest level. I am playing better and better every day and I had to play a little bit better this match."
On the marathon victory of his next opponent Verdasco, Nadal added: "Yes that was long but I played in Australia five hours, 15 minutes in semi-finals, and I had to play the final one day later," Nadal said.
"I was very tired, but I was ready. I think for sure he's going to be ready."
In Wednesday's quarter-finals, Federer will face Sweden's Robin Soderling, the fifth seed, while third seed Novak Djokovic takes on Frenchman Gael Monfils.