Federer turns to Henman's old coach to give him a fresh viewpoint

The Americans love to innovate and when the US Open begins here today television viewers will for the first time be able to hear some of what is being said by the players' entourages in Arthur Ashe Stadium.

With microphones installed in the players' boxes on the main show court, there is no doubt who will be the main focus of attention when Roger Federer meets Argentina's Brian Dabul in his opening match tonight.

The former world No 1 confirmed on Saturday that Paul Annacone, who used to work with Pete Sampras and Tim Henman, is to become a permanent member of his coaching team. The American still has some loose ends to tie up before his current contract with the Lawn Tennis Association expires in November, but he will be in Federer's corner, working alongside Severin Luthi, the Swiss Davis Cup captain, at the year's final Grand Slam event.

After going out in the quarter-finals at both the French Open and Wimbledon, his loss in Paris ending a record run of 23 successive appearances in Grand Slam semi-finals, Federer felt it was time to inject some new thinking into his game. Although he has not had a full-time coach for seven years, he has benefited from part-time arrangements in the past with Tony Roche and Jose Higueras.

Annacone has been working with Federer for a month and the results of their collaboration have been clear in the renewed attacking edge to his play. Given that Annacone coached two of the best serve-and-volley players of the modern era, it is no surprise that the world No 2 has been serving more effectively and putting more aggression into his returns. In his two Masters Series tournaments since working with Annacone, Federer reached the final in Toronto, losing to Andy Murray, and won in Cincinnati, his first title since the Australian Open.

"It's just nice to hear a fresh, different voice for a change," Federer said. "He's a very nice guy and he's very calm and speaks from experience as a player and a coach. I guess he also had kids early as a player, so he knows how to handle that. I think the dynamics work really well. With Severin, Paul and me coming into the conversation just makes it really interesting. I can go with a very clear mindset into the matches."

Federer has an outstanding record here, his run of five successive titles and 41 victories having ended only in last year's final against Juan Martin del Potro, who is unable to defend his crown because of a wrist injury. In the previous two US Opens Federer beat Novak Djokovic and Murray, currently No 3 and No 4 in the world respectively, in the final.

There is no doubt who the Americans would like to see Federer meet in this year's final, assuming that none of their own players are good enough to make it. Rafael Nadal, who replaced Federer as world No 1 with his triumphs this summer in the French Open and Wimbledon, has played the Swiss 21 times, winning on 14 occasions, but they have not faced each other on American soil since their first two meetings, in Miami in 2004 and 2005.

Nadal has won all three of the other Grand Slam tournaments but has never gone beyond the semi-finals here, having fallen at the penultimate hurdle to Murray in 2008 and to Del Potro last year. The combination of the heat, Wilson balls and the zippy surface make the conditions arguably the fastest of any of the Grand Slam tournaments, which is not ideal for Nadal's big-swinging ground strokes.

The Spaniard has also arrived at Flushing Meadows in less than peak condition in the past because of his suspect knees and the pounding his body had taken earlier in the year. He has had further treatment to his knees this summer and although he looked below his best in Toronto and Cincinnati he says he is in good shape, certainly better than he was at this stage of previous seasons.

Nadal insisted he had no hang-ups about his comparatively moderate record here. "I hope I have more chances to play well here and to have the chance to win, but without obsession," he said. "I am more than happy with what I have at home, all the tournaments that I have won. It is more than I dreamed five or six years ago, so I am happy for that. Now I have the desire to improve my tennis to play well here. That's what I am trying to do all the time."

Federer believes the tournament is wide open – "Rafa, Murray and Djokovic are all looking good, too, so I think it's going to be a US Open with multiple favourites," he said – and Murray in particular has every reason to feel confident going into a Grand Slam tournament where he feels very much at home.

"I think there are very small differences required," Murray said when asked what he needed to do to make the next step up to winning his first Grand Slam title, having lost to Federer in the finals here in 2008 and in Melbourne at the start of this year. "Nothing drastic has to change. I just need to play my best tennis for the whole two weeks and hopefully I can do that here."

Having parted company with Miles Maclagan, Murray is without a coach, although he will be assisted here by Alex Corretja, who has been a part-time member of his entourage for the past two years. Although the Spaniard is generally quite calm while watching matches, other members of his entourage – particularly his mother, Judy – will no doubt be heard over the next fortnight.

Coaching from the sidelines is forbidden, but the rule is regularly abused and the new microphones in the player boxes could pick up some interesting comments. Federer, for example, has complained in the past about Toni Nadal coaching his nephew during matches.

Murray said: "Maybe once when I was working with Brad [Gilbert] I got a warning for coaching, but there's no coaching from the people I work with, just encouragement, a lot of 'come-on', 'you can do it', and those sort of things. I think for a few of the players it will be a bit of a wake-up call. It would be good if what was being said in the box went to the umpire, which I think they probably should do at most of the tournaments. It's something that players have got away with in the past."