Ireland kept alive their dream of a first Grand Slam for 61 years with a hard-fought win over Scotland.
The Scots led 12-9 at half-time as Chris Paterson traded penalties with Ireland's Ronan O'Gara, who became the leading Six Nations points scorer.
Replacement Jamie Heaslip's try after the break turned the match and gave Ireland the lead for the first time.
O'Gara's conversion, a drop-goal and another penalty were enough to set up a title decider in Wales next weekend.
The unbeaten Irish lead the Six Nations table by two points from Wales, who struggled to a narrow victory over Italy in Rome.
It was a great win - Kidney
The Welsh need to beat Ireland by 13 points at the Millennium Stadium to win the title, while France, who play England on Sunday, are also still in the mix.
The pressure of a potential Grand Slam seemed to be weighing heavily on Irish shoulders in the first half at Murrayfield, while a fired-up Scotland came out determined to record only their second win of the campaign.
Paterson and O'Gara traded early penalties before Scotland edged into a 9-3 lead after 20 minutes.
Ireland were warming up, though, and when another penalty came their way after a period of pressure O'Gara slotted the kick to overtake England's Jonny Wilkinson as the leading points scorer in Five/Six Nations history.
O'Gara, on song again after missing four of six kicks against England in Dublin, moved to 481 points, with Wilkinson on 479 and Wales' retired kicker Neil Jenkins on 406.
The frenetic, slightly scrappy opening continued and Scotland went six points clear when Ireland prop John Hayes was penalised for taking a backward step to wheel a scrum.
But Scotland gifted the three points straight back from the kick-off when Jason White fumbled his catch and John Barclay caught the ball offside.
In the fading minutes of the half, Scotland went close to scoring the first try when Thom Evans countered from his own half.
The left wing gathered his own chip-ahead and stepped past O'Gara before offloading to the supporting Phil Godman, but the fly-half was thundered into touch by a retreating Brian O'Driscoll just a few metres short of the Irish line.
If Scotland had shown more energy in the first period, it was Ireland who came out with more vigour after the break and they put the home side under increasing pressure.
The Scottish line-out, particularly, was creaking and under-fire coach Frank Hadden replaced White with the fit-again Nathan Hines.
O'Gara happy with victory and points record
But from the next line-out Ireland scrum-half Peter Stringer took a quick tap off the top and scampered through the Scottish defence before offloading to Heaslip, a first-half replacement for number eight Denis Leamy, to crash over.
O'Gara converted and stroked a drop-goal through the posts shortly after to create some daylight before Paterson's fifth penalty narrowed the gap to four points.
The Irish fly-half missed his first kick on 65 minutes but made amends shortly after to take his side a converted try in front.
Scotland seemed to sense the match was slipping away, and though they battled to keep Ireland out for the remainder of the match, the visitors were always on the front foot and will march to Cardiff with history beckoning.
Paterson, Danielli, M. Evans, Morrison, T. Evans, Godman, Blair, Dickinson, Ford, Murray, White, Hamilton, Strokosch, Barclay, Taylor.
De Luca for Morrison (70), Cusiter for Blair (51), Hall for Ford (57), Hines for White (50), Gray for Barclay (67).
Kearney, Bowe, B. O'Driscoll, D'Arcy, Fitzgerald, O'Gara, Stringer, Horan, Best, Hayes, O'Callaghan, O'Connell, Ferris, D. Wallace, Leamy.
Murphy for Kearney (75), O'Leary for Stringer (65), Flannery for Best (61), Heaslip for Leamy (30).
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