Federer was watched by 13,943 fans as he beat Karen Khachanov 6-3, 7-6 at the Perth Arena, the highest ever attendance at the Hopman Cup.
The Swiss broke his own record in the process but revealed that the packed houses are one of the main reasons he is still playing professional tennis at the age of 36.
“It’s not normal [to have this many people turn up],” Federer said.
“You have to work so hard for it to happen. People come out to watch you practice. That was the weirdest thing that ever happened to me.
“When I turned world No 1 playing in Australia back in 2004, I remember going to Rotterdam and going to practice barely warmed up because it was an easy hit and there were a few hundred people at the practice. I was like ‘what are they doing here? Why would you go watch somebody practise? It’s the matches that matter!’.
“But I really don’t take it for granted and I think that’s what keeps me on tour. If I had to play on the outside courts or stadiums that were not full at all, I think the passion would go away a bit even though I love tennis and what I do.
“I can’t thank you enough every single time I stand here.”
Federer has at least one more match to play in Perth when Switzerland face the US in their final tie of the group stage of the team tournament.
He had already cruised past Yuichi Sugita in straight sets on Saturday before overcoming Khachanov, although the Russian saved two match points before finally succumbing.
And Federer paid tribute to the attitude of his 21-year-old opponent in the match’s biggest moments.
“I try to work hard and hopefully it pays off when it gets tough but also experience helps sometimes [in the crucial points],” Federer added.
“It’s good to be free-swinging, young and – I don’t want to say not caring – but I remember those days, it’s great. You’re match point down and you go for it.
“That’s what you’ve got to remind yourself when you’re older too: just go for it. It was a good match.
“I get the pleasure to always play on centre court in front of great crowds and usually they’re on my side which is helpful for me.”