Roger Federer US Open 2015 3rd Round
Roger Federer is a picture of grace during his third round match against Philipp Kohlschreiber in the US Open 2015Reuters

Those big, booming serves and a potentially partisan crowd is what Roger Federer will have to overcome when the Swiss legend faces John Isner in the fourth round of the 2015 US Open on Monday.

Federer has been his usual sublime self in this US Open, gliding past opponents like they were not even there. And while the third round 6-3, 6-4, 6-4 win over Philipp Kohlschreiber was far from a Sunday morning stroll, Federer was still way too good for the No.29 seed.

"I got off with a good start and held my serve throughout the first set," Federer said. "Then, I don't know, I lost a little bit on my serve. There was hardly any rallies anymore. I couldn't play as many rallies as I was hoping to, especially on the return games, because I thought he was doing a good job doing the 1-2 punch.

"Then that's not much rhythm, to be quite honest. I think because of my serve and no rhythm, I might have gotten broken as well a couple of times in sets two and three. It's exactly those kind of matches I need to win.

"Especially if I drop serve, I still find a way and I don't want to say comfortably, but I get maybe a little bit lucky at times, but also push luck on my side. When I had the opportunities I was effective again. I think I won the big points better than he did today. He's a quality player, so at the end of the day it's a really, really good win for me."

Next up for Federer is a different challenge in the big-serving Isner, who also has been quite impressive in this US Open. While Federer has done well against big servers in the past, the Swiss master admitted the Isner serve is not one that he has entirely been able to solve.

"For some reason I feel like I don't know it [Isner's serve] as well," Federer added. "I don't know how many times we have played against each other, so I don't know it that well. He's got the power. It needs to be, and then clearly because he's so tall clearly he finds the impossible angles for us, really.

"And he's got a great second serve, as well. Obviously best-of-three-set match he's even more dangerous. Best-of-five you feel like you have a bit more time, but clearly he can also run three, four, five sets serving great. It's going to be a tough match."

Isner, the No.13 seed, has not lost a set in this US Open either, and you never know, if the crowd gets behind him – and that is far from a given, considering the kind of support Federer gets, irrespective of the location and opponent – the American might just be able to push the great man.

"It's going to be fun," Isner said. "It's what I work so hard for, to get an opportunity like this. On Monday I'm going to have fun with it. At the same time, I'm going to go out there and believe that I can win the match."

Where to Watch Live

Get the Isner vs Federer Report and Score HERE

Get the Murray vs Anderson Report and Score HERE

John Isner vs Roger Federer will be the second match of the night session at the Arthur Ashe Stadium, with the first match -- between Petra Kvitova and Johanna Konta -- set for a 7 pm local time (4.30 am IST, 12 am BST) start. Live TV coverage of the fourth round match will be on Ten Sports in India, while the match can also be watched via online live streaming online on Ten Sports Live.

Viewers in the US can watch the Federer vs Isner match live on ESPN, while the live stream option is on Watch ESPN.

UK viewers can catch Roger Federer vs John Isner live on Sky Sports, with the online live streaming option on Sky Go.

Audience in Australia can watch Federer vs Kohlschreiber live on Fox Sports, while the fourth round action of the US Open 2015 can also be live streamed on Foxtel Play.

Also read