Tim Henman
Former British number one on BBC TV at Wimbledon

In 11 years you have to keep improving. If you don't improve in this game you will get overtaken by the next generation.

When you talk about Federer and Nadal, they have certainly become more aggressive.

Today, the intensity has to be there from the word go. With Rafa I have no doubt it will be. Can Federer start quickly? We'll have to wait and see.

John McEnroe
Three-time Wimbledon singles champion on BBC Radio 5 Live

The best match I ever saw was Nadal v Federer in 2008. These guys are better than ever. We're lucky to have this. Rafa looks the best I've ever seen him at Wimbledon.

Sometimes we have hyperbole building up a match but this one deserves it. I've picked Federer in fives sets. I'm hoping for a great five-setter either way.

It may be eleven years since these two have met at Wimbledon, but they met on both previous years at the All England Club before that 2008 match.

In 2007, it was Federer that came through a five-set final, clinching his fifth straight Wimbledon title.

Image source, Getty

In 2006, the first in a trilogy of Rafa-Roger finals, Federer ended a run of five successive defeats by Nadal to win in four sets.

"It was important for me to win a final against him and beat him for a change, and the easiest way was at Wimbledon," said Federer.

Image source, Getty Images

Overall Roger Federer leads their grass head-to-head 2-1.

Chandragupta: I've watched the highlights of the 2008 Wimbledon Final dozens of times but that first point still gives me goosebumps. The greatest rivalry in any sport that I've followed in my lifetime. No pressure on both of them providing a repeat

Jonathan Jurejko
BBC Sport at Wimbledon

Image source, Getty Images

Boris Becker also talked about his memories of that epic 2008 final and says it is without question in the top five of the greatest matches ever played.

"What I remember the most about the 2008 final is how could they play in darkness! It was so dark.," says the German.

"They probably would have only been to play one more game, maximum, then it would have been called off and we'd have had a Monday final.

"Roger was the favourite so it was a big upset that Rafa won.

"You go through the great Wimbledon matches - Borg v McEnroe in 1980, Arthur Ashe winning in 1975 and I'd like to think my win in 1985 will be something to be remembered!

"You have these matches that go over time and people remember them 30 or 40 years later. If you think of the five greatest tennis matches then it would be one of the five."

Jonathan Jurejko
BBC Sport at Wimbledon

Image source, Getty Images

Had a quick natter with Boris Becker - who himself has created some of Wimbledon's most memorable matches - about #Fedal40.

"Often we see matches being overhyped but you can't overhype this one - and rightly so," says the three-time champion.

"Usually I make predictions easily but this one is really difficult - I'm staying on the fence!

"A lot depends on a few points here and there, there isn't a clear favourite.

"I'm expecting a long match and the longer it goes the better it is for Rafa.

"I'm leaning maybe 51% to Rafa and 49% to Roger!"

John McEnroe
Three-time Wimbledon singles champion on BBC TV

I've watched a lot of tennis over the last 40 years. The match in 2008 was the greatest match I've ever seen. If it's anywhere near that, we're in for a treat.

Christopher Walker: Going to savour every moment of this. Could be the last time at Wimbledon. Could be the last time at a Grand Slam. Please let it be good.

Image source, Getty Images

"To me, it was the greatest match I'd ever watched, the greatest match ever played anywhere."

Take a walk down memory lane with this superb piece which retells the story of Roger and Rafa's 2008 final via seven-time Grand Slam champion McEnroe, who commentated on the match for NBC, umpire Pascal Maria, long-time Wimbledon locker-room attendant Doug Dickson,and Jonathan Overend - the BBC's tennis correspondent from 2003 to 2013.

This is their first meeting at Wimbledon since 2008's epic, late-night five-set ding-dong final.

It finished 21:15 BST local time with Rafael Nadal, spreadeagled on the baseline in delight at his first Wimbledon title.

What a day, what a match.

Image source, Reuters

Cats or dogs.

Cashmere or leather.

Grace or fury.

Sweat-free or snarl-packed.

Roger or Rafa.

However you like life, whoever you have in this second semi-final, strap in for the fourth and possibly final meeting of Federer and Nadal at Wimbledon.

Annabel Croft
Former British number one on BBC Radio 5 Live

Tennis players are out there with nowhere to hide. Your psyche is out there for everyone to pick at.

Djokovic is so focused and is so intense and he maintains that for the whole match.

You can't afford the little drop-offs that many players get - something Bautista Agut had at points today.

More from Djokovic on BBC One:

"I had to dig deep. It's the semi-finals and Roberto was playing his first Grand Slam semi-final. He was not overwhelmed.

"He played really well. He was managing his nerves in the first set but later on he established himself and started to play better.

"I got a bit tight. It was a close opening four or five games of the third set - that's where the match could have gone a different way. I'm glad it went my way."

On the next semi-final between Nadal and Federer:

"I will watch it. My coaches will see the whole match.

"I'll definitely see parts of it. I'm a fan of that match-up as well. It's one of the most epic rivalries of all time so it's fantastic to see them play today."

Image source, Getty Images

Novak Djokovic speaking to BBC TV after his win:

"This has been the dream tournament for me since I was a child so to be in another final is a dream come true.

"Regardless of the history and many finals I've played, playing finals at Wimbledon is something different so I'll definitely enjoy that experience."

Image source, Getty Images

Are you going to be watching Fedal, Novak? "Of course I will be watching!"

Novak Djokovic tells BBC One Roberto Bautista Agut wasn't overwhelmed by the Centre Court experience.

"He played really well!"

Annabel Croft
Former British number one on BBC Radio 5 Live

We saw how much tension was coursing through his body in this match alone.

But Djokovic dealt with it and he found a way with that high level of focus and concentration.

Image source, EPA

It's a wonderful life: When Roger, Rafa + Novak finally retire, we'll see a return to a more ordinary level of professional tennis. The next gen won't necessarily surpass them. If anything, their superhuman achievements have prevented younger players from believing in themselves.

John McEnroe
Three-time Wimbledon singles champion on BBC TV

Roberto Bautista Agut lifted his game in the second set. The important thing, Djokovic outclasses him and played the type of tennis that has helped him win this thing four times.

Image source, Getty Images

Roberto Bautista Agut, who has had a sensational tournament, waits for Djokovic before walking off court.