England v Wales in Six Nations: Jeremy Guscott & Jonathan Davies

England and Wales are the only unbeaten sides in this season's Six Nations

The last time these two sides met, Wales effectively knocked England out of their own World Cup with a thrilling come-from-behind victory at Twickenham.

Even in the context of a long and dramatic history between the two sides that stretches back to 1881, it was an encounter of epic proportions.

On Saturday, they meet at Twickenham again in the Six Nations, Wales confident and with a strengthened team, England desperate for revenge and looking to move within one win of a Grand Slam.

It's the perfect scenario - old enemies, childhood friends and a Triple Crown to boot - but who is going to win?

Let England legend Jeremy Guscott and Wales great Jonathan Davies guide you through the issues.

The very best of enemies

Davies: The battle of childhood friends Billy Vunipola and Taulupe Faletau - the latter even lived with the Vunipolas while at sixth form - is one to relish.

But who comes out on top in the battle of the two number eights will be dictated by which of them gets the most secure platform from their team-mates.

At the moment Wales' Faletau is the best number eight in world. He's a total all-round player, as shown by his incredible stats in this Six Nations.

Billy Vunipola is a different sort of player, a big ball carrier who causes huge problems for defences - he gives England attacking options and gets them on the front foot.

We will see more of what Vunipola does because it is eye-catching, but while he is the best number eight carrying in midfield, Faletau is the best number eight overall - he has a wider skillset.

Guscott: I'm sure no quarter will be given by either Vunipola or Faletau. They have grown up playing against, as well as alongside, each other. They will look forward to a good tear-up on the pitch and a good catch-up afterwards.

Faletau is much more athletic and uses his feet to evade defenders, whereas Vunipola will draw on his power and weight to help him dominate the contact.

The difference continues in how they play the game.

Vunipola is involved more in attack than defence - getting his hands on the ball more than any other player in the tournament with 58 carries.

Faletau is the opposite, racking up a competition-high of 51 tackles.

If Wales can stop Vunipola they will believe they go a long way to stopping England.

Blind-side flanker Dan Lydiate is likely to be given the responsibility. It is a decent-enough theory, but Dan will have to tidy up his tackling technique after being heavily penalised for failing to wrap his arms in recent games.

Read more: Teams, preview & stats

Remember what happened last time…?

Wales scrum-half Gareth Davies scores the decisive try in the two teams' World Cup meeting

Guscott: The defeat by Wales at the Rugby World Cup in September should motivate England rather than plant any doubts in the minds.

I was part of the England team that lost a Grand Slam decider to Scotland back in 1990. A lot of our players would pull on the memory of that game to help motivate themselves for years to come.

If England lose on Saturday, some in the media will point at it being a hangover from the result six months ago.

However unless England get a decent lead and let it slip or give away too many penalties as they did in the World Cup, I don't believe we can reference it.

The latter of those two things is the more likely. England gave away 12 penalties against Ireland, 15 against Italy and 12 against Scotland - more than the defeated opposition in each match.

Prop Dan Cole has a fair few to his name, while captain Dylan Hartley and back-row pair James Haskell and Chris Robshaw need to be careful as well.

Davies: Wales' win in the World Cup will be a huge motivational factor for England, but there's no doubt the visitors will go into the game full of confidence.

They had so many injuries before that game it is difficult to understand how they won.

Wales will be stronger on Saturday and a better all-round side - now they have all their players fit they will be more of an attacking threat.

But England are also looking better under Eddie Jones. They are more confident and feeling less pressure, as the new coach takes it off the team.

Who will win the key areas?

Davies: The breakdown is always key and Wales have the advantage.

Jones could have picked Maro Itoje at six, with the returning Joe Launchbury and George Kruis in the second row, to give his back row more dynamism.

Instead he has stuck with the industry and experience of Robshaw at blind-side and the physicality of Haskell at open-side.

If Wales can get parity in the scrum, it will play a huge part in the result.

We know Wales have an excellent power game but - and this is not criticism - I think they have the ability to play the game differently when required.

If Plan A is not working on Saturday then I'd like to see them look to go outside 13 and use the pace and guile of Liam Williams, George North and Alex Cuthbert out wide.

Guscott: England centre Manu Tuilagi may not have played for England since June 2014, but he can still have an impact, as part of a bench full of big ball-carriers.

Suddenly being required to keep quiet a player with his power after playing 50 or 60 minutes yourself is a tough ask.

I do not envy Dan Biggar, Jamie Roberts and Jonathan Davies.

England have the slightly stronger bench and Tuilagi can run home any England advantage or create the chance that decides a tight game.

Why will England win?

Guscott: Ultimately, I don't think they will.

I hope England can win playing the heads-up rugby we've seen so far from them, with their backs scoring good tries.

A win in that style would go a long way to changing our rugby landscape which is still too focused on defence.

However, I believe Wales will prevail because of their experience of seeing out these winner-take-all matches and the fine-tuning that defence coach Shaun Edwards will have done with his side.

Why will Wales win?

Davies: I don't know if they will. If the scrum is good Wales will win because individually they are better players, but whoever goes best collectively will win it.

Home advantage is a huge factor and either way it will be very tight, but if Wales play to their potential they will win.

Scores?

Guscott: Wales by two.

Davies: Wales by three or four. Unless the scrum doesn't go well, in which case England by six to nine.

England have a solitary win more than their neighbours and age-old rivals