Wales vs. England: 5 Key Battles That Will Shape 2015 Six Nations Clash

Wales and England get this year's Six Nations off to a booming start on Friday evening, where the head-to-head at Cardiff's Millennium Stadium brings with it a potential 2015 title decider.

Stuart Lancaster has suffered a gradual increase in squad injuries of late, but the England coach will strive to see that his remaining resources are sufficient to achieve back-to-back wins over the Welsh.

However, Warren Gatland's men are in better health and seek to defend their borders as they did in 2013, where a record 30-3 win over the English visitors sealed that year's Six Nations crown.

Read on for discussion of the five key battles likely to decide the tie.

1. Dan Biggar vs. George Ford

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It's almost a blessing in disguise that Owen Farrell is out of the 2015 Six Nations running due to injury, leaving George Ford free to reign as England's standout fly-half option with less pressure.

Without Farrell's presence, England have a new reliance on the Bath talisman, which he could come to thrive upon and excel as part of the international fold.

With Gareth Anscombe's introduction to the Welsh ranks, Dan Biggar has yet more to prove against the English, but this season's form at Ospreys may mean he's capable of fending off the threat.

Biggar remains Gatland's first-choice playmaker and bears a huge pressure to perform in Cardiff's tournament opener, where England's back-row bastions are sure to be flying up in an attempt to see him crumble.

Twenty-one-year-old Ford sits as the less experienced of the two in terms of caps, but Biggar is still searching for a cemented spot at No. 10, particularly in a World Cup year, and Anscombe's sitting as an enticing alternative.

Taking full advantage of any kicking opportunities will be key to seeing which of these two sides emerges as the victor at the Millennium Stadium, but both Ford and Biggar each promise to inject a keen carrying game into the fray.

2. Sam Warburton vs. Chris Robshaw

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It's a battle that for the past few years has always been looked upon as one that tends to turn the tide of this fixture, with captains Sam Warburton and Chris Robshaw set to collide once again this weekend.

The open-side struggle pits two of Europe's finest flankers against one another, but the differing styles these two bring to the role usually means head-to-head clashes aren't always what makes their meeting so intriguing.

Since taking the England captaincy, Robshaw has brought his tackling exploits to new heights and consistently features as his team's most active defender.

Warburton, a more natural asset in the No. 7 jersey, performs a different duty and may reckon more fiercely in the carrying stakes, but the breakdown is where this pair will contend for supremacy.

Few players in the Six Nations will rack up more mileage than Warburton and Robshaw around the park and their tendency to protect grounded ball and attempt to steal possession is likely to help in turning the tide.

3. Jamie Roberts vs. Luther Burrell

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While the English midfield is a position of hot debate and ambiguous interpretation, Gatland knows full well who will pioneer his centres this year, with few players in finer form than No. 12 Jamie Roberts.

The Racing Metro bulldozer has been terrific on the club stage of late and if Wales are to rediscover their edge in attack, he'll be considered a crucial catalyst in unlocking their back line's potential.

Lancaster, meanwhile, has chosen Luther Burrell as the man to begin England's tournament at inside centre with Bath man Jonathan Joseph set for his Six Nations debut in the No. 13 jersey, per BBC Sport.

In his current vein of form, it doesn't seem as though there are any out there capable of stopping Roberts, with a lot of Friday's pressure on Joseph concerning the defensive side of things.

Should the Welsh warrior succeed in frequently building a platform for the likes of Jonathan Davies and George North to build from, the hosts may be capable of recreating a victory akin to that of 2013's 30-3 win.

Let there not be a complete focus on Wales' man of the hour, however. Burrell flashed signs of brilliance in last year's Six Nations and is a well-rounded asset at his best, capable in both piercing defences on his own, as well as laying groundwork for Joseph to run off.

However, limiting Roberts will be a top priority for the Northampton Saints star and a lot will ride on how he deals with quelling that threat in particular.

4. Taulupe Faletau vs. Billy Vunipola

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Injury to Gloucester's Ben Morgan means Billy Vunipola and Taulupe Faletau are once again primed for a family feud on Friday, with the two cousins taking centre stage as the No. 8 titans are poised to make Cardiff tremble.

Morgan's stellar form in the autumn meant that Vunipola dropped to an unfamiliar spot on England's bench, but his form with Saracens has since improved markedly, while Faletau remains a force for Gatland's side.

The Newport Gwent Dragons star is a potential game-changer in his own right, who if found at his pick-and-go best, can expect to lead this Welsh pack against their weakened English counterparts.

However, despite suffering from absences, Friday's visitors still have some serious weight to throw around and Vunipola will be one of those peeling off the back of every ruck and maul looking to make ground of his own.

It promises to be a tug-of-war between giants and the blood connection only serves as extra motivation for the two cousins as they go in search of individual bragging rights as much as wins for their respective teams.

5. Leigh Halfpenny vs. Mike Brown

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Leigh Halfpenny's place as Gatland's starting full-back is no longer assured, but the Toulon maestro has managed to keep his place for the Six Nations opener despite increasing pressure from Scarlets' Liam Williams.

Some may argue Williams brings a less restrained running presence to the No. 15 jersey, but it seems the boot of Halfpenny and his calmer temperament in defence are still preferred by the coaching staff.

Mike Brown's role doesn't suffer from the same competition for England's full-back, especially now that Ben Foden is out of the tournament with injury, but his influence is no less fearsome.

Last year's Six Nations Player of the Tournament perhaps doesn't have the same excitement surrounding his name coming into this year's competition, but bypassing his fine defensive figure will be no less difficult for the home team.

Speaking on the 30-3 loss in Cardiff two years ago, per PA Sport (h/t ESPN Scrum), Brown said:

"

That was one of the lowest experiences of my rugby career and it's in the back of the mind. With everything that was riding on the game, it was obviously massively disappointing to lose in the way we did. It was a closer game than most people will have you believe, we just didn't take our chances on the day and ended up doing not too well.

It was a game that could have swung in our direction because there were momentum shifts, but then we chased the game and it got away from us.

"

The new-look centre partnership may require Brown's aid to offer a more familiar contribution going forward, but the full-back's main concern lies in ensuring Halfpenny can't profit through any aerial assaults Wales might launch.

Biggar will be looking to release his full-back wherever possible, but Brown is a stingy guardian of such territory, who will also be hoping to utilise his tactical nous in stifling Wales' running game whenever his opposite man comes into the line.