Ireland vs. Scotland: 5 Key Battles in International Match

Ireland welcome Scotland to Lansdowne Road on Saturday for their latest World Cup warm-up, having dealt Vern Cotter's men a 40-10 humiliation earlier this year en route to claiming the Six Nations title.

Coach Joe Schmidt was left in good spirits last Saturday when his experimental lineup claimed a decisive 35-21 victory against Wales at the Millennium Stadium, but a heavy summer workload is still in its early phases.

The Scots have a boost of their own after Tom Hamilton of ESPN Scrum announced on Wednesday that Cotter's deal had been extended to 2017, showing the confidence they have in the project their helmsman is building.

Dublin is braced for a Celtic clash this weekend, as stars both established and otherwise look to cement their World Cup spots. Click on for a selection of the most important head-to-head battles.

1. Simon Zebo vs. Ruaridh Jackson

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In the pursuit of proving he has more strings to his bow, Simon Zebo makes for a surprise selection at full-back for Ireland this Saturday, a position it's hard to remember him taking up in the past.

Schmidt's desire for versatility demands more of the winger, it would seem, and Zebo has given the impression he's willing to answer that call when speaking on the matter, via Patrick McCarry of JOE.ie:

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I think the [coaches] know I can do a job at full back,' he says. 'I don’t need to plead my case. I’ve played internationally at full back, I’ve played full back for Munster and I really enjoy playing there. I get more of the ball, it’s a position I love playing – I played there in the Champions Cup against Sale and got man of the match, I love playing there, when I get my hands on the ball that’s when I’m at my best.

I think the coaching staff know the attributes and pros and cons of each player so it’s just going to be about playing the best you can in the warm-up games and doing as best you can.

"

It's good to see, then, that the Munster isn't short on confidence in his ability playing from the back.

There was a portion of the win over Wales last week where Zebo slotted into a more central channel and looked effective, but Scotland's Ruaridh Jackson will put up a fight as the man trying to stop him in Dublin.

Jackson is also coming out of his natural habitat, as Cotter runs the rule over whether his playmaker can be a viable option at No. 15. This presents a fascinating duel between two who would look to thrive outside their respective comfort zones.

Rather than either "full-back" dazzling, per se, Saturday's Test could rest largely on which of the two commits fewer errors while exploiting any openings his counterpart might offer.

2. Sean O'Brien vs. David Denton

A fit-again Sean O'Brien got on the scoreboard twice the last time these two sides met one another and helped tremendously to inspire Ireland to the win that clinched their 2015 Six Nations triumph.

David Denton was on the receiving end of that Man of the Match performance, except this time O'Brien promises to be a more direct threat, as the Tullow Tank makes an interesting switch to No. 8.

What does that mean? For starters, one can certainly foresee O'Brien's carrying numbers increasing, and after Jamie Heaslip found such rampant success against Wales last week, that back-row dynamic appears to be working well.

Edinburgh's Denton is a powerful figure to contend with, though, and has talismanic potential of his own when able to find his stride; he's a keen carrier and a useful, heavy unit to have in the Scottish pack.

O'Brien may not be taking Heaslip's jersey anytime soon, but Saturday gives the Leinster powerhouse an opportunity to exercise some considerable muscle.

3. Jared Payne vs. Richie Vernon

A good 18 months or so after first making his migration into the centre, former flanker Richie Vernon now finds himself as a more regular face in Scotland's midfield and is slated for another start on Saturday.

Up against him at Lansdowne Road comes Jared Payne, a man who also managed to score at Murrayfield back in March, which remains his only international try to date.

Although Ulster's Payne is far more accustomed to playing outside centre, Vernon's 102-kilogram, 6'5" frame has proved useful at Glasgow, largely due to some surprising speed and a good technical grasp of the game.

Payne may not be as physically imposing as the Dundee native, but that only makes the battle of the No. 13s all the more interesting. Will the battering ram or the slighter key have more success?

4. Chris Henry vs. Hugh Blake

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Tauranga-born Hugh Blake will make a much-awaited debut for Scotland as part of a back row that boasts not a single member who was raised in the country he represents.

That fact, as well as Cotter's selection policy, is currently causing a stir in Scottish circles, but it's widely held that Blake is a top talent in his own right, preparing for his first season with Glasgow Warriors.

Ireland's Chris Henry, on the other hand, is no new face to Schmidt, and while Tommy O'Donnell's dislocated hip is a tragic loss for the team, Henry will consider his World Cup chances buoyed as a result.

A blocked blood vessel gave Henry serious concern last year, but the Ulster star is settled back into the national team these days, going about proving his credentials once more under Schmidt.

Controversial though the presence of Blake might be, there's no doubting Cotter's investment as a seriously bright prospect with a nothing-to-lose mentality Henry would be unwise to underestimate. 

5. Ian Madigan vs. Greig Tonks

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Ian Madigan's place at the World Cup isn't wrapped up just yet, and the fly-half knows Saturday provides a prime opportunity to strut his stuff against susceptible opposition.

Paddy Jackson got his turn against Wales in Cardiff, but Schmidt can very much be influenced by a dazzling display against the Scots, something of which Leinster's backup is entirely capable.

In a strange jumbling of the order, Greig Tonks has swapped roles with the aforementioned Jackson this weekend, and the former will hope his run-out at No. 10 can bear fruit.

Having played there in the past, Tonks may be no stranger to the position, but the wily Madigan will be all but too happy to mop up any errors committed.