Wales can't afford any Six Nations slip-ups - Charteris

Luke Charteris accepts there can be no margin for error as Wales face a history-making quest to be crowned RBS 6 Nations champions this season.

No team has ever won the title after drawing a game, but that is the task now awaiting Wales and Ireland following Sunday's 16-16 draw in Dublin.

Wales did it the hard way in 2013, bouncing back from an opening weekend loss to Ireland by reeling off four successive wins and claiming Six Nations silverware on points difference from England.

Starting next Saturday when Scotland arrive in Cardiff, Wales must realistically win three homes games -- France and Italy are also due at the Principality Stadium -- and topple England at Twickenham to maintain hopes of finishing top.

"We have to win all four," Wales lock Charteris said. "We saw last year how close this tournament has been over the last few years. Unfortunately, there is no Grand Slam or Triple Crown to go for now, but we have to knuckle down and get four wins from four.

"I saw a bit of the [Scotland versus England] game, and they [Scotland] looked good. It was a physical game against England -- both packs went at it -- and they will be a challenge, especially with us having one day less recovery, so we will have to look after ourselves."

Wales head coach Warren Gatland is scheduled to name his team for the Scotland clash on Wednesday, with fly-half Dan Biggar the leading injury concern following his first-half departure with an ankle injury.

He was replaced by Rhys Priestland, whose goal-kicking helped haul Wales back into the contest from 13-0 adrift, with Gatland confirming immediately after the match that Biggar had suffered a sprained ankle.

Full-back Gareth Anscombe, who was selected to start the game, withdrew because of a tight hamstring and was replaced by Liam Williams.

Reflecting on the Ireland encounter, Charteris added: "We spoke about getting a strong start, and we didn't do that. Ireland got on top of us for the first 20 to 30 minutes. Credit to them, they kept the ball well, got across the gain-line a bit too easily, and that made it tough for us.

"Unfortunately, we have had a few slow starts, but we have been around long enough as a team and we back our fitness and back our composure.

"No-one panicked out there. They played well at the start and we had to address it and slowly but surely we clawed ourselves back into the game.

"I thought we did well to come back. We dug deep to get out of a hole and we went through I don't know how many phases in that passage of play to get the three points [after 74 minutes], then unfortunately gave three back very cheaply straight after that.

"I thought Rhys came on and played very well to be fair. He certainly gave us opportunities to win the game. We keep saying we are lucky that we have that strength in depth in terms of players. When Gareth (Anscombe) pulled out, Liam stood in and played very well. You need to have that."