James said:" Samoa are playing very good rugby at the moment and we know they are a physical bunch so this week again it will be a massive game up front for the forwards.
"We have got to get our heads switched on and get ready for this physical battle. We will have to keep working them and hopefully that will open up some gaps."
He said training had been tough during the week but the Welsh players were delighted to get the vote of confidence from Head Coach Warren Gatland.
And he explained that the team will be going into the Sunday game confident they are ready.
He said: "We have worked hard this week in training and everyone is switched on and ready for the challenge. We've just got to make sure we stay focused on our own game and know what we are doing so we can go into this game with confidence.
"There is no doubt we are going to have to be on top of our game this weekend and if we get our game plan right we will be fine. I thought as a pack we did well against South Africa but we are all just focused on this weekend's game now."