Taulupe Faletau will thrive under pressure for places - Wales boss Rob Howley
Wales boss Rob Howley has backed number eight Taulupe Faletau to thrive amid the intense pressure created by a fierce battle for back-row places.
Faletau has missed out on a Wales starting berth for the second successive RBS 6 Nations game, with Howley retaining a back-row trio of Sam Warburton, Justin Tipuric and Ross Moriarty against Scotland at Murrayfield on Saturday.
Bath forward Faletau has won just three of his 63 caps off the bench, underlining what an integral figure he is in the Wales set-up, but Moriarty's performance in defeat to England 12 days ago made an irresistible selection case.
"Any player will tell you that they want to be put under pressure and they want competition for places," Howley said.
"We've got four world-class back-row forwards there, and it is genuinely a great headache to have, to have a world-class player on the bench.
"I am sure it will drive Toby (Faletau) on. He hasn't missed many games and has been a constant in the national team.
"He will be a constant in the (match-day) 23 for the future, and has a huge challenge with Ross, who has been outstanding.
"There is more growth in Ross and another level in him. He has shown deft skill, his work-rate and he emptied the tank against England if you look at the GPS data."
Wales' bench for Edinburgh is reinforced by the presence of Faletau's Bath colleague - experienced lock Luke Charteris - and Howley wants more of an impact from his substitutes this weekend than was the case against England.
"You learn off the best as players and coaches, and you look at the All Blacks, in particular, when they go to the bench on 50-55 minutes and (those players) make a difference," he added.
"That is what didn't happen against England, and hopefully it will be different at Murrayfield.
"When you make changes, you expect impact. We feel that we've got a strong bench, and need to develop competition. Players coming on have to make a better impact than they did against England."
Wales will face a Scotland side showing five changes from the one beaten by France, with injuries sidelining key players like Greig Laidlaw, Josh Strauss and Sean Maitland.
And Howley's team are also chasing a 10th successive victory over their opponents, having not lost in the fixture since seven Chris Paterson penalties condemned them to a 21-9 defeat 10 years ago.
Howley believes the contact area and subsequent back-row battle will be critical, while Wales will also look to apply pressure on Scotland's new number eight and scrum-half combination of Ryan Wilson and Ali Price, who makes his first Six Nations start.
But the return after injury of George North could also be crucial to Wales' victory hopes, with the giant Northampton wing hoping to increase his Test try tally of 28.
"He just missed out against England, and he is a player who gets supporters off seats whenever he gets the ball," Howley said.
"We want him with ball in hand as often as possible, because he is very athletic and powerful.
"His try against Scotland 12 months ago summed up how he can change games, and he will be looking to have a huge influence.
"Scotland have a strong back-three with ball in hand with Stuart Hogg, (Tim) Visser and (Tommy) Seymour working hard off the ball.
"It will be a good contest within a contest because they are all players who want to get their hands on the ball and make people enjoy the game."
Wales captain Alun Wyn Jones, meanwhile, accepts his team must be on guard, especially as Scotland caught Ireland out earlier this month with some unexpected, pre-planned attacking options.
" We've seen the willingness Scotland have to use the ball, and marry that with some of the funny things they've displayed from set-piece, then we have to be on our guard and expect the unexpected," Jones said.
"We have to expected the unexpected - particularly from a team which is on a high."