|Six Nations: Wales v Scotland|
|Date: Saturday, 13 February Venue: Principality Stadium, Cardiff Kick-off: 16:50 GMT|
|Coverage: Live on BBC One, commentary on Radio 5 live sports extra, BBC Radio Wales, BBC Radio Cymru & BBC Sport website and BBC Sport app, plus live text commentary.|
Lock Luke Charteris says Wales cannot afford any more slip-ups if they are to win this season's Six Nations.
Wales began their campaign with a 16-16 draw against holders Ireland in Dublin on Sunday.
No team has ever won the title after drawing a game and Charteris says there can be no margin for error.
"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," Racing 92's Charteris said.
"We saw last year how close this tournament has been over the last few years."
Warren Gatland's side must realistically win three homes games against Scotland, France and Italy and beat England at Twickenham to maintain hopes of finishing top.
Wales were crowned Six Nations champions in 2013 on points difference from England after four successive wins following an opening defeat by Ireland.
They next face Scotland at the Principality Stadium on Saturday, with the visitors having lost 15-9 to England in their opening game.
Charteris said Scotland "looked good" against Eddie Jones' side despite the defeat at Murrayfield.
"It was a physical game against England," Charteris said.
"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."
|This weekend's live TV coverage|
|Sat, 13 Feb (14:25)||France v Ireland||BBC One|
|Sat, 13 Feb (16:50)||Wales v Scotland||BBC One|
|Sun, 14 Feb (14:00)||Italy v England||ITV|
|Six Nations coverage on the BBC|