Shanklin is far from downbeat about Wales' prospects, despite Ireland's 100% start to the championship and their fine record in Cardiff.
"We've got to come out firing against them, like we did against England, and test them early on," said Shanklin.
"We've got to hit them hard as they come at us. It was very disappointing against Scotland after we stepped up a gear against England. We lost the Scotland game in the first-half, but we've got to move on from that.
"We are nearly there. We are not playing for 80 minutes, but we need to do that against Ireland to stand a chance of winning.
"We've got a massive challenge ahead of us on Saturday - a bigger challenge, in my opinion, than playing against England."