Five-time champion and world No. 2 in ranking Roger Federer trounced Germany's Philipp Kohlschreiber via a commanding 6-3 6-4 6-4, to reach the fourth round of the U.S. Open, reported  BBC.

The 34-year-old Swiss player will now face13th seed John Isner, 30, of the United States.

Before this week, Federer has never been past the second round at a Grand Slam, according to BBC. However, since hiring Stefan Edberg to his coaching team in December 2013, the world's second seeded tennis player saw improvements in his game with new movements and fresh approaches to the next to make an improved counter attacks against the baseline prowess of his rivals, including Novak Djokovic and Andy Murray.

Federer commented on relapsing to his old habit of advancing in behind his return against a practice session with Frenchman Benoit Paire during the Cincinnati Masters event in August, "I said, 'OK, I'm going to chip and charge and just keep the points short. I'm tired. I want to get off the court soon anyway'. That's when I started to run in and hit returns. I hit a couple for a winner. They were like ridiculous.

"I tried it the next practice and it still worked. That's when [coach] Severin Luthi said, 'Well, what about using it in a match?' I was like, 'Really?'

'We sort of came up with that name, 'sneak attack by Roger' or 'Sabr' for short. I don't know. Call it 'Fed Attack', call it whatever you want."

Victoria Azarenka Emerges as Biggest Threat to Serena Williams' Grand Slam Year

Meanwhile, former world No. 1 and currently 20^th-seeded Victoria Azarenka of Belarus is making a fierce career comeback and has emerged as the biggest threat to Serena Williams' imminent calendar-year Grand Slam, after demolishing No. 11 Angelique Kerber of Germany in their impressive third-round match 7-5, 2-6, 6-4, ESPN reported.

Azarenka survived the game which lasted for two hours and 52 minutes. She described the match as good for women and the women's tennis as a whole.

"I think it goes beyond tennis," Azarenka commented. "It's just in general in life, women have to always prove a little bit more. In business, in other sports. But, you know, I just want to show it on the court and not talk about it. I think today everybody saw what's been happening out there. I hope they can appreciate that."

Before facing Kerber, Azarenka sais she reviewed some handwritten reminders from hitting partner Sascha Bajin who has been inventing a new motivational language. "Pinish," Azarenka said as the one that hits her the most. "That's one word [hitting partner] Sascha [Bsajin] uses a lot. It's a combination of finish and punish."

Azarenka will now be facing unseeded American Varvara Lepchenko, who reached the fourth round for the first time in her career. Lepchenko beat Mona Barthel of Germany 1-6, 6-3, 6-4 and is the only American still in the game's bottom half.