World number one Novak Djokovic gave a masterclass in Thursday's US Open night session as he demolished Argentina's Carlos Berlocq 6-0 6-0 6-2.
Djokovic arrived in New York having lost just two matches in what is becoming one of the greatest ever years in tennis, and he remains formidable.
Berlocq, ranked 74th, could not live with the Serb's pace and took 66 minutes to get a game on the board.
Five-time champion Roger Federer earlier beat Dudi Sela 6-3 6-2 6-2.
But that was nothing compared to the performance given by Djokovic on the same Arthur Ashe Stadium several hours later.
"The first two sets were ideal," he said. "I could not play better. I was getting a lot of balls back, I was ending the points when I needed to. I was making a lot of winners. My serve was okay, and my return was great.
"I felt fantastic on the court. And there is not much I can say when everything seems fun and seems enjoyable when you're playing such good tennis."
Berlocq might be a relative journeyman of the sport at 28 and with a career-high ranking of 50, but he did little wrong against Djokovic.
The 24-year-old Serb was magnificent from the baseline, hitting with relentless pace and accuracy, and not even the gathering support, or compassion, of the New York crowd could help Berlocq.
The Argentine did at least avoid the ignominy of becoming the first man in 24 years to suffer a 'triple bagel' - losing all three sets without winning a game - at the US Open when he broke serve early in the third set.
Berlocq would break again in an entertaining final set that also saw Djokovic win a point with a between-the-legs shot, moments before closing out the match after 90 minutes.
"We are professionals on the court," Djokovic added. "We need to do our job, obviously to win, regardless of who is across the net. I know Carlos off the court. He is a nice guy. Today on the court I had an answer for every shot. I played great.
"I felt a little bit for him in a certain stage of the match in the third set where he was trying really hard to get back into the match. I have to give him credit for fighting."
Federer was comfortable in his match against Sela, easing to victory over the world number 93 from Israel in just 77 minutes on a warm but windy afternoon on.
"I didn't have much trouble on my serve, and from the baseline I also had the upper hand," said Federer. "When it's like that, obviously it's tough for the opponent.
"I just think I was superior today."
Federer will play 27th seed Marin Cilic in the last 32 after the Croatian thrashed Australian rising star Bernard Tomic 6-1 6-0 6-2.
Seventh seed Gael Monfils crashed out, losing 7-6 (7-5) 5-7 6-7 (5-7) 6-4 6-4 to Spain's Juan Carlos Ferrero.
Monfils paid the price for an erratic display that saw him hit 21 aces and make 81 winners as well as 81 unforced errors in a thrilling match that lasted almost five hours.
Both players received a standing ovation from the crowd on Louis Armstrong Stadium before the final game, which Ferrero served out to love.
"When it was 5-4 in the fifth set, I felt very special on the court," he said. "I mean, when you saw this crowd enjoying all the time during the match. They love this kind of match, so it's great to be in there."
Eighth seed and leading American Mardy Fish had an impressive 6-2 6-2 6-4 win over Tunisian Malek Jaziri, and ninth seed Tomas Berdych swept past Fabio Fognini 7-5 6-0 6-0.
Jo-Wilfried Tsonga, the 11th seed, easily saw off Ukrainian Sergei Bubka 6-3 7-5 6-2. The Frenchman will play 19th seed Fernando Verdasco in round three after the Spaniard beat Marsel Ilhan of Turkey 6-4 6-3 6-1.
Radek Stepanek, the 23rd seed, became the latest player to withdraw in a week of casualties when he retired trailing 6-4 6-1 2-0 against Juan Monaco with a shoulder problem.