Based in Las Vegas, Darren Cahill was widely seen as the perfect solution to Federer's coaching dilemma.
"It (the nine-day trial) was a test," Federer explained.Last month, Cahill resigned as coach of the Australian Davis Cup team after two years in the job, citing business and personal reasons.
"We said 'Let's see how it goes first and then go back and let's think about it'."
"He went back (to the US). He told me it was tough for him to do the travelling with his kids and everything."
"The weeks required, he couldn't really do so we never really got to the point where I had to go and think about it and take a decision on my own."
"He took the decision for me and it's all right. We had a good time, we worked hard, we spoke a lot."
So Federer will continue to work with Severin Luthi, Switzerland's Davis Cup captain, on a part-time basis.
He is seen here practicing for ATP Indian Wells masters 1000.
(Via news.com.au; Images by Robert Laberge/Getty Images)