US Open 2015: Roger Federer on the charge ahead of all-Swiss semi-final clash with Stan Wawrinka

When you have won a record 17 Grand Slam singles titles and led the world rankings for more weeks than any player in history it might seem there is little left to accomplish, but Roger Federer could be on the brink of arguably his greatest achievement yet.

At the age of 34 the world No 2 is through to the last four of the US Open here for the 10th time in the last 12 years. Playing in his 64th successive Grand Slam tournament, a record, Federer is the only one of the semi-finalists yet to drop a set. He is just two wins away from becoming the oldest men’s singles champion here since Ken Rosewall won the title at 35 years and 10 months in 1970.

In beating Richard Gasquet 6-3, 6-3, 6-1 in just 87 minutes in the quarter-finals Federer still found time to hit 50 winners. In the semi-finals he will face Stan Wawrinka, his friend and Davis Cup colleague, who was an equally emphatic winner, beating Andy Murray’s conqueror Kevin Anderson 6-4, 6-4, 6-0. Novak Djokovic takes on Marin Cilic in the other semi-final.

Federer is still developing as a player, having come up with a new shot this summer, which has been labelled a “SABR” (“stealth attack by Roger”) by his entourage. When returning, even against some of the biggest servers, Federer occasionally charges forward towards the service line to hit a half-volley. The server, taken by surprise, often puts the ball wide or long in trying to hit a passing shot, knowing that Federer will be more than likely to put away any volleying opportunities.

“For many years now I have tried to look at the big picture to hopefully still be playing at a high level at this age, so in some ways I am not surprised I am playing as well as I am,” Federer said. “I have worked on my game moving forward, have been able to take the ball earlier, and I think I’m volleying better than I have the last 10 years. I think I was volleying well coming up on the tour when I was younger because I was spending more time at the net.

“I think that gave me confidence to keep working on that, moving forward. Now because my serving is working quite well, you put those two things together, and standing in on the return as well, I think has changed the dynamics a little bit. It’s all about keeping yourself in shape and staying injury-free – and motivated, I guess.”

Taking care of his body, particularly in terms of his pre-match preparations and in getting nine or 10 hours’ sleep every night, has been particularly important.

“I guess I’m more professional these days, whereas when I was coming up on tour I would bounce up and down for two minutes and then just walk out to the practice and do almost the same for the match,” he said. “These days I take more time, put in more of the core exercises, do more stretching. Sometimes I just can’t wait to get off the [treatment] table again, honestly. It’s nice not to be on there all the time.

“Sleeping has become quite important. I make sure I sleep enough, as well. When I went to bed after the Isner match [in the fourth round] it got quite late and I couldn’t sleep quite as much as I wanted to. Because I believe it’s really the sleep that gives you energy again down the road. That’s why the next two days are very important for me in terms of sleeping.”

Wawrinka’s victory ensured that the Swiss No 2 became the fourth player to qualify for the Barclays ATP World Tour Finals in London in November. Federer, Djokovic and Andy Murray have also booked their places in the season-ending tournament.