"I told them after all these years I still go out and train, trying to improve. So I think it starts to make sense to them more and more now. Of course, they realise it as well, especially in sports, or in school, reading and writing and all that stuff, it's all coming along. So I think they see the benefit of hanging around with the same theme or subject for a while."
One reporter then followed with: "Is the reverse of that ever true? Do your daughters ever say to you, 'Dad, do this or do that? Why do you do that?' Do they ever talk about tennis to you in any way?"
Federer proceeded to detail the very unusual advice his children had passed on to him to mix it up a little on court.
"Yeah, the one thing in tennis they tell me is I should ... play on the lines. They think that's a good thing. I was like, 'OK, I'll try that,'" the 34-year-old father of four explained.
"The other one said that maybe you should look that way and play the other way. I said, 'OK, I'll try that, too. It's not as easy as you think it is, but I'll try.'
"That was actually quite funny. When they came to practice the other day, they asked me to do the trick. I was like, 'Which one?' 'The one where you look the one way and play the other way.' So they have given me advice, if you like, yeah. They're good coaches, yeah (laughs)."
The questions about family life didn't end there, either.
Reporter: "With the girls, and the [twin] boys, too, do you feel there's anything they're missing in a stable at-home environment? You get to take them out on the road and they get to see the world, but is there a flipside to that?"
Federer: "Yeah, it would be great to have the same bed for three months in a row, which would help with sleeping rhythm or whatever it is. But we're used to this life. It's the only thing they know and I know really for the last 20 years, if you like.
"So it's OK. But, of course, there is benefits of being in one place, or for us now only being in Switzerland would be beautiful. We could go much more in the countryside, catch up with where you put them in a proper school and all that.
"Then again, we have tons of friends and family that come join us on the road. Honestly, they're not just all by themselves and all that stuff. They're kept very busy. They have a ton of friends on the road, which I think is really important for them."
Federer stormed into his 12th quarter-final at the Australian Open to extend his record for most quarter-finals at the first slam of the year.
It also brings up Federer's 47th grand slam quarter-final, which is the most last-eight appearances in the Open era ahead of Jimmy Connors.
He will face Tomas Berdych in the last eight after the Czech sixth seed battled past Spain's Roberto Bautista Agut 4-6 6-4 6-3 1-6 6-3. -- news.com.au