NEW YORK -- He stepped onto the Arthur Ashe Stadium court shortly before midnight Monday looking like a man with a gun to his head.
The rain, forecast to arrive three hours earlier, was -- quite literally -- in the air. You could feel it, and so could Roger Federer. A worst-case scenario of extended matches -- Fish-Tsonga, then Wozniacki-Kuznetsova -- had left Federer with a narrow window to defeat Juan Monaco of Argentina.
"I know there's actually a lot of rain coming tomorrow, right?" Federer said later. "So that was more the part that worried me than actually maybe having to go on and off the court the whole night. There was not much margin there for us because it was already so late.
"So one rain delay and probably they would have sent everybody home."
Instead, it was Federer who sent everyone home at 1:13 a.m. ET. In a clinical, thoroughly professional performance, he defeated Monaco 6-1, 6-2, 6-0. It was over in a tidy 82 minutes, and a surprisingly large portion of the crowd of 24,000 -- well over half -- stayed to watch most of the match.
Federer was rewarded for his sense of urgency when Tuesday's matches, night and day, were cancelled early Tuesday afternoon.
The score, believe it or not, failed to completely reflect his dominance. But try this statistic: Federer stroked 42 winners, while Monaco had only four.
A light rain began to fall in the third set, but referee Brian Earley allowed play to continue. Federer has won 16 Grand Slam singles titles, but he said he still gets anxious when the schedule is in flux.
"Something happens tonight, you see the women's match, you warm up several times, you wait, maybe have to eat something, you relax again," he said. "Your body is also jumping out of your skin because you want to go, then you're held back again. It's tough.
"It's crazy how our schedules change all the time. As tennis players, it makes it extremely difficult to be on your A-game every single day. I'm extremely pleased with my reaction out there. I played really well, crisp, nice. I felt fantastic."
Federer, the No. 3 seed, has now advanced to the quarterfinals in 30 consecutive majors, a number that is hard to process.
He has won 12 of 13 sets and, with more rain in the forecast, can look forward, perhaps, to a few days off before playing Jo-Wilfried Tsonga.
Can Federer win this thing? Can he win his sixth U.S. Open title in eight years?
"I think so," Federer said. "Actually, in all the Grand Slams this year I've played really well. Australian Open, I played great. I think the match with [Novak] Djokovic was extremely close. The French, clearly I was right there [against Rafael Nadal]. Wimbledon I thought I was really close as well.
"Here again, I'm showing good form. So it's up to me now to get on a good run for the end of the tournament."
2. Advantage Fed, Djokovic : Although Federer and Djokovic -- both fourth-round winners Monday -- undoubtedly were enjoying all the commotion about the weather, it was having an adverse impact on Andy Murray and Nadal.
Murray practiced indoors Tuesday morning in preparation for his match with 22-year-old American Donald Young. The two played earlier this year at Indian Wells, and Young beat him in straight sets. Rafa will meet Gilles Muller, but when will they get on the court?
If the forecast is right, it might not be until Thursday, which means Nadal and Murray will have to squeeze an extra match into a compressed schedule. A Monday men's final -- or even Tuesday -- seems likely.
3. Fitness goes only so far: Djokovic is enjoying his first ride as the world's No. 1 player. The biggest reason for his sudden success is between the ears.
"Physically, out there, there are so many fit players," he said after reaching the quarterfinals and an encounter with countryman Janko Tipsarevic. "I mean, the game has changed tremendously. Top hundred players, physically there is not much difference between No. 78 in the world and No. 2, 3, 1, 5.
"But it's a mental ability to handle the pressure, to play well at the right moments, and that's why I think there is a certain difference with top-10 players."
4. Fed-Tsonga II: You probably remember the last time these two met. It was at Wimbledon, and it was extraordinary.
For the 179th time in his career, Federer found himself with a two-set lead. But for the first time, he lost. Tsonga rallied to win 3-6, 6-7 (3), 6-4, 6-4, 6-4 and knock Federer out of his favorite tournament.
"I'm just excited to play against him, honestly," Federer said. "He's a nice player to watch and also to play against. It's very interesting. I thought we had a great match at Wimbledon, which I unfortunately ended up losing. But I thought I was playing great tennis and shouldn't have [lost], but look, he did well and came back. And he proved it in Montreal how good he's playing right now. He's definitely on a good streak. I hope I can stop him this time.
"Look, I live for the big matches; live for playing a guy who is explosive, has got some firepower. I like to play those kind of players, especially now that we're in the deeper stages of the tournament."
So, how long did that loss linger?
"Not much, actually," Federer said. "For some reason, because I felt I did everything I could. I didn't walk away too down. I was more frustrated for a little bit because I knew I was playing good enough to win the tournament. That's what is tough about it, especially at Wimbledon, which means so much to me. But it's what happened. It's tough. It's never happened at a Grand Slam that I was up two sets to love and ended up losing.
"I did enjoy my vacation, so it's OK."
Greg Garber is a senior writer for ESPN.com.