Ireland encountered few difficulties at Dubarry Park in Athlone last night as they set up a Grand Slam decider against England next weekend.
But while the Irish defence, which has only conceded one try this season, was rarely troubled by a poor Scottish side, Mike Ruddock's men will need a major improvement if they are to lift the championship.
Ultimately, though, they did all that was required of them and finished strongly to cross for a couple of tries as the Scots wilted.
The large crowd expected Scotland, who had lost all three games prior to this, to fade after Ireland blitzed them in the opening minutes with a superb individual try from Shane Layden.
The former Roscommon minor footballer, playing on his club ground, collected a Scottish clearance on halfway, dinked the ball over the initial tackler and then showed awesome pace to sprint down the left to score after four minutes.
Captain Paddy Jackson, who had missed with a 40-metre penalty after two minutes, was just off target with the touchline conversion.
The Scottish scrum and line-out was in all sorts of trouble in the opening quarter, but while Ireland dominated in terms of possession, they did not hammer home their advantage.
Another break from Layden created the opening which led to Scotland conceding another penalty after 14 minutes, which Jackson converted from in front of the posts.
But Ireland were not able to add to that 8-0 lead and Scotland were let off the hook by some sloppy play from the home side, despite some great work by JJ Hanrahan in the centre.
Layden needed to be at his most alert to beat Scotland winger Michael Crawley to the ball as the visitors broke from deep after 25 minutes and entered the home '22' for the first time.
Moments later, out-half Harry Leonard, who has played half a dozen games for Edinburgh in the Pro12 this season, was off target with a penalty from the right, while Jackson also missed from 45 metres three minutes from the break. Two more penalties from Jackson secured the win after the restart for Ireland, before the superb scrum-half Luke McGrath raced over for their second try after 63 minutes off the back of a scrum.
Jackson added the points to make it 21-0 and they sealed the issue seven minutes from time when No 8 Jack Conan barged over from close range to set up the showdown with England -- who play France away tonight -- next Friday evening.
Ireland -- S Layden; C Finn, C Farrell, JJ Hanrahan (S Olding 71), F Horan; P Jackson (C Marsh 69), L McGrath (K Marmion 69); K McCall (J Cawley 71), J Rael (C O'Connell 69), P Reilly (D Merrey 58); I Henderson, D Qualter (T Beirne 63); C Gilsenan, A Conneely (J Coghlan 46), J Conan.
Scotland -- T Allan; J Farndale, M Bennett (R Ferguson, 60), F Russell, M Crawley (T Steven 68); H Leonard, M Torrance (M McConnell 52); R Hislop (J Bhatti 71), G Turner (R Anderson, 62), A Allan (G Robertson 72); A Redmayne (A Sinclair 47), J Gray; M Eadie, W Bordill, J Swanson (C Reid 68).
Ref -- M Raynal (France).