The Saracens man knows that if Wales are to record their first victory over Ireland in Cardiff since 1983, they must produce a similar effort to their Round 2 performance against England.
'We've got to come out firing against Ireland, like we did against England, and test them early on,' he said.
'We've got to hit them hard as they come at us."
Wales and Ireland teams
Defeat in Scotland means Wales prop up the Six Nations table, but Shanklin knows if Wales put in a solid show for the whole game, this may be the match where the duck is broken.
'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.'
Williams sounds warning
Wales have been heavily criticised at times during this year's tournament, and Shanklin knows his side must get a good start in order to test the Irish at the home of Welsh rugby
'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,' he added.
Humphreys hails Ireland