Roger Federer and Rafael Nadal remain on course for a blockbuster semi-final showdown and their first Wimbledon meeting since their classic final in 2008.

Incredibly, the two most successful male players in history have not faced each other on the grass at SW19 since Nadal claimed his first title, 9-7 in the fifth, 11 years ago in what is widely regarded as the greatest match in the history of the Championships.

The next obstacles standing in their way, in the fourth round, are big-serving Italian Matteo Berrettini and gritty Portuguese 30-year-old Joao Sousa.

Berrettini is a lively outsider enjoying a decent grass-court season who saved four match points in beating Diego Schwartzman in five sets.

Federer will be facing the 23-year-old for the first time, and he said: "I don't know him very well, so that makes it a bit more tricky.

"I saw him play a little bit in Halle and I saw his run in Stuttgart. Now he's backing it up here again. That's not easy to do, especially when you're sort of newer on the tour.

"That's the way to go – start winning, going deep in those. You gain momentum, you start rolling at the bigger events. He did exactly that. I almost played him in the Halle finals when he ran into (David) Goffin, who I thought played a great match.

"I'm expecting a tough one. I hope he has no energy left. I'm sure he'll recover. He's young. I'm sure we'll see a tough match on Monday."

Berrettini was six when Federer lifted his first Wimbledon trophy.

"When I was a child playing tennis I was looking at him, the best player. I was cheering for him," he said.

"He's a player who when he's winning matches, he's a super dangerous opponent against everybody. He is very quick, very good physical performance. He's aggressive with his shots, he's going for the shots all the time.

"He's a player that, sometimes he loses matches during the whole year. But when he starts to have a positive dynamic, is very, very dangerous."

Elsewhere, top seed Novak Djokovic continues the defence of his title against Ugo Humbert, Kei Nishikori plays Mikhail Kukushkin, David Goffin faces Fernando Verdasco and Guido Pella takes on Milos Raonic.

There is an all-American affair between Sam Querrey and Tennys Sandgren while Roberto Bautista Agut comes up against Benoit Paire.