Pat Rafter said he was unable to have an impact on troubled Australian tennis player Bernard Tomic as he reflected on his unenjoyable spell as Davis Cup captain.

Rafter was responding to comments made by Tomic, who labelled the two-time US Open champion as "not much of a nice guy" and added that the Australian icon likes to "put on a show".

Tomic was speaking in an interview after he sparked backlash in the wake of his straight-sets loss at Wimbledon last month, when he told a news conference he was "bored" during the loss to Mischa Zverev.

In response to Tomic's criticism, Rafter was relatively subdued as he revealed his struggles in relating to the 24 year-old, who is 9-15 on the ATP Tour this year.

"He's not entirely wrong, at the end of the day we do wear different hats for different occasions," Rafter told KIIS FM. "I do put on different faces for different occasions.

"I don't want to bash up on Bernie. He's got a point and he's got a voice and he can say what he wants to say. We have had run-ins, we see life a little bit differently."

Rafter spent four years in charge of Australia's Davis Cup team and the 44 year-old had his issues with Tomic during that time.

Tomic was labelled "disgraceful" by Rafter after his US Open loss to Andy Roddick in 2012, while the world number 73 hit out at Tennis Australia for its lack of support three years later.

"I'm really honest with the guys. I came into a time in tennis – Davis Cup-wise and also as performance director – to try and change the culture and I realised I had no impact on these guys whatsoever and they couldn't relate to me and I couldn't relate to them," Rafter said.

"It's probably a lot of bad timing. I wanted to try and bring back some really strong, ethical morals we used to live by and I just found I couldn't do it.

"It wasn't enjoyable. I reckon I had one or two enjoyable ties out of my four years that I did it for and it was just hard work. I was banging my head against a wall all the time.

"I just wasn't in the mood for that kind of thing. I didn't need it in my life.

"I thought at the time we [Rafter and Tomic] could make some change but I found out pretty quickly that I couldn't impact that," Rafter added.

"That was the era we got brought up with [where criticism would spark change]. I'm not sure this generation takes that sort of criticism as positive criticism."