Rob Howley: Back row will be crucial at Murrayfield

Reigning RBS 6 Nations champions Wales will arrive at Murrayfield on Saturday on the back of five successive victories against Scotland.

But Wales boss Rob Howley is braced for a fierce challenge when his team tackle opponents chasing a third win on the bounce for the first time in Six Nations history.

While Wales revived their campaign following a home loss to Ireland by winning on the road in both Paris and Rome, Scotland sent Italy and Ireland packing from Murrayfield.

They were results that kept both countries in title contention behind tournament favourites and Grand Slam-chasing England, although Saturday's losers will drop out of the running.

Scotland last beat Wales when seven Chris Paterson penalties secured a 21-9 verdict in 2007. The five subsequent meetings have seen them concede 15 tries and 138 points.

Howley, though, has watched enough of Scotland during this season's Six Nations to know that a third successive Murrayfield triumph would represent a considerable achievement by his players.

"Scotland have been really impressive, having to defend without much possession. And they have played some good rugby," Howley said.

"When you look at their individuals - their back-three against our back-three - it is going to be some game in terms of counter-attacking and ball in hand.

"Dean Ryan (forwards coach) has given them a steely edge, and the breakdown area will be key. They are at home and will fancy their chances.

"They have played particularly well and they have done something this year that we have not in beating Ireland at home. We could not manage that accolade.

"We have come out on the right side in the last couple of years in this fixture, and we will need that attitude again on Saturday.

"We were fortunate to beat them at the Millennium Stadium (in 2010) through a Shane Williams try in the last minute. They should have beaten us, and they were more physical than us in the contact area.

"When you look at their matches in the last 18 months, they might have come out on the other side. The margins are small.

"They have done enough to win games, but that is international sport and we have been there."

One key to any Welsh hopes of victory will be winning the back-row battle, where skipper Ryan Jones, recalled 2012 Grand Slam captain Sam Warburton and number eight Toby Faletau have huge roles to play.

"It is just a slight edge in the breakdown and contact area, decision-making skills," added Howley, reflecting on the decision to select Warburton instead of his fellow openside Justin Tipuric.

"'Warby has proved that in those areas in the last 18 months. It was not an easy decision to make, and we pondered about it.

"We have to celebrate that we have two fantastic sevens, not Justin against Warby. I do not get that. They are two mature, well-grounded kids who just want to go out and play."