Asked what Carter would have thought to see him now with a world record 20 grand slam titles, Federer broke down.
"Sorry. Oh, man, I still miss him so much. I hope he would be proud," Federer said.
"Geez, never broke down like this," he said later.
According to 'The Roger Federer Story: Quest for Perfection,' a book penned by Swiss tennis journalist Rene Stauffer, Federer "was never so upset in his life" when he was told of Carter's death while playing in the Canadian Masters in Toronto.
The Australian newspaper reported he left his hotel and "ran through the streets, bawling and hysterical".
Federer told CNN it was a career-changing moment. "He didn't want me to be a wasted talent. It was somewhat of a wake-up call for me when he passed away, I really started to train hard," he said.
"I've been incredibly fortunate to have the right people at the right time, the right coaches at the right time. Sure, I make those decisions but I've been lucky along the way."
Federer regularly pays for Carter's parents to travel from Adelaide to Melbourne to sit in his players box at the Australian Open each year — and he's hopeful of putting on a show in 2019 as he seeks to defend his title.
"Am I confident? I don't know. I feel good. I've been training really well. I've had another great year. Still happy playing and I've won the last two Australian Open editions so I should be going in there with confidence," he said.
"I love playing Australia, love playing in Melbourne. There's so much that connects me to that country. The legends that I admire, the coaches that I've had in Tony Roche and Peter Carter — they've been incredibly inspirational and important to me in my life."
