London - Roger Federer marked the 10th anniversary of his epic Wimbledon final loss to Rafael Nadal by claiming his rivalry with the Spaniard is the equal of the battle between football superstars Lionel Messi and Cristiano Ronaldo.
Federer will start his bid for a ninth Wimbledon title against Serbia's Dusan Lajovic on Centre Court on Monday.
But, on the eve of the Swiss star's 20th Wimbledon, the defending champion's mind drifted back to the evening he was dethroned by Nadal in a classic final widely regarded as the greatest match ever played.
Federer had beaten Nadal in two previous Wimbledon finals before the Spaniard knocked him off his perch in 2008 with a five-set thriller lasting almost five hours and late into the evening in front of an enthralled global audience of millions.
It was the match that cemented Federer and Nadal as the giants of their generation and accelerated the sport's resurgence as a multi-million pound industry.
Nadal's triumph -- his first at Wimbledon -- fuelled an epic rivalry that reminds Federer of the way Barcelona striker Messi and Real Madrid forward Ronaldo have slugged it out for the top prizes in football.
"Sure, yeah. They have a long-standing rivalry. I have the same with Rafa," Federer said when asked if he could see similarities between the rivalries.
"They're very different from one another. I guess there's some similarities there as well.
"As similar as we are, Rafa and myself, we're still very different on many levels. I think it's pretty much the same for them.
"Obviously in football, it's different because you're only as good as your team. The pitch is huge, with 11 of them running around.
"With us, we're a little more in control, let's be honest. I hope I can control it a bit better than they could."
Like Messi and Ronaldo, both Federer and Nadal have showed astonishing longevity, splitting the last six Grand Slam titles with three each.
Federer now has 20 major titles to his name, while Nadal clinched his 17th by winning the recent French Open.- Painful memories -
Nadal arrives at Wimbledon as world number one, with defending champion Federer one place behind him.
And, while Messi and Ronaldo have flopped out of the World Cup in Russia, with Argentina and Portugal both eliminated on Saturday, Federer and Nadal could easily clash in 10th anniversary final reunion later this month.
For Federer, that would bring back painful memories of one of the most difficult defeats of his glittering career.
"I think it was one of the hardest losses I ever had, no doubt about it. I was so close to making it six in a row," Federer said.
"It was a great match for many reasons. It also made me more human potentially, the loss under the circumstances.
"We go back in time with Rafa. I'm sure that we'll talk about it when we're older in the rocking chair.
"We'll talk about how it all was. I'm sure I took something away from it, but mostly positive, even though the moment was pretty hard naturally."
Before he can contemplate avenging that loss, Federer's immediate aim is to avoid a first round wobble against world number 57 Lajovic.
Despite all his experience, playing the first match on Centre Court is still an anxious moment for Federer, who skipped the clay-court season to stay fresh for Wimbledon.
"I think it remains a little bit nerve-wracking, in all honesty. It's a big deal," said Federer, who won the Wimbledon warm-up at Stuttgart, but lost in the Halle final to Borna Coric last weekend.
"I mean, besides the history and the mythical place that it is, you cannot also practice on it.
"When you come out, there's a bit of uncertainty for both players, from a very quiet week and site that we've seen this week, it's just packed everywhere.
"The entire atmosphere changes at Wimbledon, and you realise the eyes are on you. It's a massive honour."