Federer and Murray remain on course
Roger Federer continued his dynamic US Open form in near-tropical conditions on Saturday, while Andy Murray remained in the hunt for his first grand slam crown.
Federer cruised past Fernando Verdasco 6-3 6-4 6-4 in two hours and two minutes, blasting seven aces and 30 winners against the 25th-seeded Spaniard.
The Swiss master, however, deviated from his normal baseline game and rushed the net 27 times, a tactic that earned him 26 points.
"I had no clue my stats were that good," he said. "Fernando did have some good chances for good passing shots. Looking back, I don't remember missing too many volleys and overheads.
"Probably half the time I didn't have to volley because it was hard to hit a good pass. It was windy. Usually when I do come in, it's probably on one I can be very offensive on."
Federer has not lost a set at the US Open this year, as he moves closer to a sixth title at the National Tennis Center.
The Swiss next faces American 23rd seed Mardy Fish, who beat Gilles Simon, the French 16th seed, 6-1, 5-7, 7-6 (7/5), 6-3.
Fish prevailed in a match which finished after 0100 local time on Sunday morning despite hitting 74 unforced errors.
Verdasco, 28, had 35 unforced errors and 10 double faults as he lost to Federer for the fifth time in as many meetings.
Murray, who won Olympic gold last month, recovered from a mid-match lapse to defeat Spain's Feliciano Lopez 7-6 7-6 4-6 7-6 in three hours and 53 minutes to reach the fourth round..
The Briton was leading 4-2 in the third set before Lopez fought back to send the match into a tense fourth set.
"The last few sets were tough," said Murray. "I just played a little bit better at the end of the tiebreaks, a little bit more solid than him, and that was the difference."
Murray said the oppressive heat made the match "mentally and physically challenging".
"I actually felt better towards the end of the match than I did maybe halfway through it," he said. "It was probably down to a combination of things, having not played that much in these conditions. It's just taking a while to get used to it.
"I usually have three weeks in Miami before the US Open but I couldn't this year because of the Olympics. It was a nice problem to have though."
A sombre Lopez said Murray deserved to win the match.
"I was two sets to love down and I was still was believing that I could make it, even a break down in the third," he said. "It was a tough, tough match. Long rallies. It was hot.
"Andy's making you always play one extra ball. It's not like I should have won but I could have won."
Third seed Murray next plays 15th-seeded Canadian Milos Raonic, who beat American James Blake 6-3 6-0 7-6 on the back of 29 aces to become the first Canadian to make the last 16 in 24 years.
Eleventh seed Nicolas Almagro kept Spanish hopes alive when he reached the fourth round for the first time with a 7-6 (7/3), 6-7 (4/7), 7-6 (7/2), 6-1 win over American wildcard Jack Sock.
Almagro will meet Czech sixth seed Tomas Berdych, who defeated American 27th seed Sam Querrey 6-7 (6/8), 6-4, 6-3, 6-2.
Croatian 12th seed Marin Cilic, a quarterfinalist in 2009, ended Asian hopes in the singles when he ousted Japanese 17th seed Kei Nishikori 6-3, 6-4, 6-7 (3/7), 6-3.
Cilic will next face unseeded Slovak Martin Klizan who beat doubles partner Jeremy Chardy, the French 32nd seed, 6-4, 6-4, 6-4.
Additional reporting from Sapa-AFP