Roger Federer, whose form has undeniably dipped since parting ways with his former coach, Australia's Tony Roche, last May, will be working with Spanish coach, José Higueras, during this week's Estoril Open with a view to making the arrangement permanent and for all tournaments, not only those on clay - as was the case with Roche.

"We want to be flexible, and we're trying things out," said the Swiss number one the day before his debut in the competition - against Belgium's Olivier Rochus, who is 80th in the ATP world rankings.

"José will be with me this week, and we'll see how it goes. He's flown over from the USA and we've been working together for three days," continued Federer. "I've been thinking about who should be my new coach for a long time now. I had several names, but not all were available."

Higueras, who rose to world number six in 1983 is now 55 years old. 15 of his 16 titles were won on clay courts and he reached the semi-finals of the Roland Garros tournament twice - in 1982 and 1983.

As a coach, he has worked with a number of top players, including Michael Chang and Jim Courier - who both won the French Open under him - as well as Pete Sampras, Todd Martin, Carlos Moyá and Sergio Bruguera.