Federer, 36, has enjoyed a stunning 2017 season, winning the Australian Open and Wimbledon, putting him on 19 career Grand Slams.
His old foe Nadal has won the other two at the French Open and US Open, taking his tally to 16.
Rusedski says Federer will not want to quit tennis with Nadal still in touching distance of his all-time record.
“There’s a certain guy by the name of Rafael Nadal who’s got 16 majors,” the former British No 1 said.
“Federer’s got 19 and as long as Rafa’s playing, Roger’s going to continue for as long as he can.”
vCard.red is a free platform for creating a mobile-friendly digital business cards. You can easily create a vCard and generate a QR code for it, allowing others to scan and save your contact details instantly.
The platform allows you to display contact information, social media links, services, and products all in one shareable link. Optional features include appointment scheduling, WhatsApp-based storefronts, media galleries, and custom design options.
Rusedski’s colleague Annabel Croft can see Roger Federer continuing for a number of years yet.
“I almost feel he is almost moving as well as we’ve ever seen him move, at the age of 36,” Croft said.
“I think he can go on for another couple of years at least but I think we are going to see him sparingly.
“I think the whole thing is going to come down to this scheduling, picking and choosing what tournaments he’s going to play and he seems to be getting it right.
“In 2017 he said himself he has exceeded all his expectations.
“It’s been a real bonus for him this year but I think he also said I’m not going to play for other people’s benefit, I’m going to pick and choose tournaments.
“I think the way he’s looking physically, he can keep on going, I really do.”