Scotland experienced heartbreak at the Millennium Stadium because, after deservedly chalking up what seemed to be an insurmountable lead, crashed to a 31-24 defeat with Wales wing Shane Williams scoring the decisive try in stoppage time.Dominant at the breakdown and regularly bursting through tackles, Scotland asserted themselves early on with John Barclay shrugging off two tackles before racing through to score.Dan Parks, named man of the match, controlled the game and it was his clever grubber kick which Max Evans managed to dot down in the corner to ensure Scotland went in at the break 18-9 ahead. But injuries to full-back Chris Paterson (rib) and wing Thom Evans (wing) forced Scotland to reshuffle their back division with replacement Mike Blair handed the unfamiliar role of wing.Nevertheless Scotland were still comfortably in the ascendancy and Parks stroked over a penalty two penalties after the interval to extend the advantage to 12 points.Moments later and an incident occurred that Scotland would later rue – Sean Lamont’s forward pass to Kelly Brown was an uncharacteristic error from the centre.But it denied Scotland a clear-cut try and had the pass been legal it is hugely unlikely that Wales would have found a way back into the match.  Lee Byrne reduced the deficit and started the Welsh comeback on 56 minutes when, following some enterprising play from Williams, he hurtled down the touchline to score in the corner.But Scotland did not seem fazed by that score and Parks responded with a magnificent long range drop-goal to make it 24-14.Replacement Scott Lawson, who had carried the ball well and made a couple of lively excursions into Wales’ territory, was yellow carded and the home side made the most of their numerical advantage.Surging forward, Leigh Halfpenny scored a try with Stephen Jones adding the extras to set up one of the most thrilling finales seen in an RBS 6 Nations match for many years.Wales cranked up the pressure and replacement Phil Godman was carded for allegedly impeding Halfpenny and, with 15 seconds of the match remaining, the hosts chose to kick the penalty which Jones duly did.At the re-start, the clock went past 80 minutes, but the drama was far from finished and 13-man Scotland again found themselves on the back-foot with an inspired Wales throwing red jerseys forward.Williams proved to be the matchwinner and the architect behind Scotland’s undeserved destruction when he popped up to slide over the whitewash to bring the curtain down on an epic encounter.Bitter disappointment for a Scotland side who had dominated the match for large periods, but some timely errors in the latter stages ultimately proved to be incredibly costly.Scotland (18) 24Tries: Barclay, M Evans Con: Paterson Pens: Parks (2) DG: Parks (2)  Scotland: Chris Paterson (Edinburgh), Thom Evans (Glasgow Warriors), Sean Lamont (Scarlets), Graeme Morrison (Glasgow Warriors), Rory Lamont (Toulon), Dan Parks, Chris Cusiter (captain) (both Glasgow Warriors); Alasdair Dickinson (Gloucester), Ross Ford (Edinburgh), Euan Murray (Northampton), Nathan Hines (Leinster), Alastair Kellock, Kelly Brown, John Barclay, Johnnie Beattie (all Glasgow Warriors).Substitutes: Scott Lawson (Gloucester), Allan Jacobsen (Edinburgh), Richie Gray (Glasgow Warriors), Alan MacDonald, Mike Blair, Phil Godman (all Edinburgh), Max Evans (Glasgow Warriors).Replacements: Lawson for Ford, Jacobsen for Dickinson, Gray for Hamilton, MacDonald for Brown, Blair for T Evans, Godman for Parks, M Evans for PatersonWales (9) 31Tries: Byrne, Halfpenny, S Williams Cons: S Jones (2) Pens: S Jones (4) Wales: Lee Byrne, Leigh Halfpenny, James Hook, Jamie Roberts, Shane Williams, Stephen Jones, Gareth Cooper; Paul James, Gareth Williams, Adam Jones, Jonathan Thomas, Alun Wyn Jones, Andy Powell, Martyn Williams, Ryan Jones (captain). Substitutes: Huw Bennett, Gethin Jenkins, Bradley Davies, Sam Warburton, Richie Rees, Andrew Bishop, Tom Shanklin.