Parks has been given the nod in the stand-off position in the first four games against France, Ireland, Italy and Wales but Ross came on as a replacement for the Australian-born player in last week's loss to Wales and did well enough to earn a start against England at Twickenham on Saturday.

But Williams insists Ross has only himself to blame for his lack of action in this season's tournament.

The coach explained: ''It has been presented as Parks versus Ross but that is not what we're about.

''We're about bringing through all the players to perform - and in our opinion Gordon performed well when he came on in the second half against Wales.

''In the first half Dan threw an interception pass which obviously knocked his confidence completely and we made a tactical decision at half-time.

''It didn't surprise me Gordon played so well and I was very happy for him.

''He's been in very good form for his club but when he has been coming to Scotland training I think there has been an air of tension about him and I talked to him about overcoming it.

''When he went on last Sunday he did very well, his communication was very high, which is what you need from your number 10 - and the players around him commented on that.

''And when things did go wrong he didn't get flustered, he kept the ship going.

''His performance in the second half earned him his opportunity so well done to him.''

Ross had no arguments about Williams' comments but the Leeds player admitted he had sympathy for Parks, who has come in for some heavy criticism in the Scots' last four games.

He said: ''I think I let myself down at training by dropping my standards of personal skills at times, either with bad execution or bad passes and that probably didn't do me any favours with selection.

''Dan and I very rarely speak about the situation, we only speak about the game and try and help each other.

''I do feel sympathy for him because it hasn't been easy for him.''