Indian Wells, California  - Roger Federer and Darren Cahill have gone their separate ways after a trial coaching run in Dubai was scuppered by a potentially killing travel schedule for the Australian.

Federer, second seed at the Indian Wells Masters, whose ATP play begins Thursday, revealed that Cahill had withdrawn from the potential all-star arrangement due to the tyranny of travel on the tour.

"We decided not to do it," said the Swiss player Wednesday after a hitting session. Federer said he will continue to work with Swiss Davis Cup skipper Severin Luethi.

"He worked with me 35 weeks last year," said three-time Indian Wells winner Federer. "The final answer is that we're moving on."

Federer flew Las Vegas-based Cahill, former mentor to Lleyton Hewitt and Andre Agassi out to his base in Dubai for a trial run.

Federer said the tennis side went fine. "It was a good time for a test. Darren rang me after the Australian Open. We'd been in contact for the past five years. I had decided to rest my back and not play Dubai and Davis Cup, so it was the perfect time to try.

"We had a good time, it was nice to have someone around. We spoke a lot.

"But Darren said it would be tough for him to do all the travelling due to his kids. It was a test to see how things would go."

Federer, still looking for his first title of 2009, said that he had to make a choice by resting his back instead of playing Davis Cup in Alabama, where Switzerland lost 4-1 to the US at the weekend.

"It was a tough decision," said the 13-time Grand Slam champion. "It had felt bad last last year and maybe I played too much then when I wasn't feeling great.

"It was a choice of playing now with some pain or resting it and being ready for the next six months.

"I always look long-term, so that's what I decided. I may have disappointed some people by not playing Davis Cup, but I knew I needed to treat my back problem." dpa