Ireland outwitted Scotland 35-25 in Dublin for an RBS 6 Nations victory that they hoped would be enough to salvage a third-place finish.
CJ Stander, Keith Earls, Conor Murray and Devin Toner all struck with tries as Ireland edged a thrilling Aviva Stadium encounter, capitalising on pivotal yellow cards for John Barclay and Alex Dunbar.
Joe Schmidt's men claimed three tries when Scotland were reduced to 14 men, leaving captain Rory Best and company hoping England could beat France in Paris to hand Ireland third place.
Johnny Sexton was sin-binned late on for Ireland for killing the ball, and that after being upended by Dunbar for the Scotland centre's earlier yellow card.
Stuart Hogg, Richie Gray and Dunbar claimed Scotland's scores, but Ireland were still able to grind home.
Schmidt's victory over close friend and former Clermont coaching colleague Vern Cotter softened Ireland's frustrating campaign, his side slipping from defending champions into mid-table.
Barclay's cheap yellow card turned an engaging first half in Ireland's favour, the Scotland flanker binned for conceding three penalties in his own 22.
Ireland plundered two tries with the Scarlets back-rower in the bin on his 50th cap, CJ Stander snaffling an astute acrobatic finish and Earls profiting from Hogg and Tommy Seymour's collision.
Schmidt's men seized on their man advantage to turn the screw via mauling and tight drives, with Munster flanker Stander eventually improvising well to launch himself over a pile of bodies and dot down.
Sexton's savvy chip behind the line set Hogg and Seymour into a panic, the duo colliding to land in a heap, with the ball popping free. Munster flyer Earls swept through, scooped up the ball and doubled Ireland's try count.
Ireland bossed the opening 15 minutes, claiming some 90 per cent possession thanks to bullish ball-carrying from the impressive Jamie Heaslip and Stander.
Sexton slotted three penalties amid the dominance, only to miss another he would expect to have nailed. Ireland's premier playmaker inexplicably opted to fire up a high bomb rather than punt deep and clear from his own 22, and paid the price to allow Scotland a foothold.
Laidlaw's penalty was a portent of danger ahead as Ireland repeated the feat of failing to clear their lines, and this time Hogg provided the punishment. The fleet-footed full-back picked the weak link in Ireland's defensive line chasing a loose kick, and duly scythed in between Rory Best and Mike Ross. The flummoxed front-rowers could only flail at Hogg's shadow as the Glasgow star cut through then romped home unopposed.
After Ireland's two-try flurry, Laidlaw landed his second penalty to close the half.
Robbie Henshaw and Andrew Trimble teed Ireland up again after the break though, racing into the Scotland 22 and eventually forcing Hogg to run into touch.
Scrum-half Murray nipped home for his seventh Ireland try after further strong mauling, with Sexton's conversion edging the hosts into a 28-13 lead.
Jared Payne's fine defensive read ought to have let Ireland steal a turnover and release some pressure, only for Tommy O'Donnell to steam into the ruck from the side and slip off his feet.
The Munster flanker's sloppy penalty not only denied Ireland the chance to clear, but also gifted Scotland a route back into the contest.
Tim Visser powered into midfield from the attacking lineout, and then Ireland captain Best completely misread the break.
The Ulster hooker raced out of an admittedly porous defensive line, gifting Richie Gray a walk-in score. Laidlaw's conversion left Scotland leading 28-20 on the hour.
Scotland sustained the pressure, at least until Alex Dunbar was sin-binned for a judo-throw cleanout on Sexton. Ireland pounced immediately, Toner diving home for the hosts' fourth and match-sealing try.
Scottish rancour for Dunbar's yellow card boiled over after the try, Cotter's men aware the game had slipped away. Referee Pascal Gauzere had to push Scotland captain Laidlaw in the chest to calm the situation, before ordering replacement Pete Horne to calm down.
The bad blood continued as Scotland attacked with intent, with Sexton eventually sin-binned for hitting a ruck from the side. Dunbar's first act after his sin-binning was to run in Scotland's third try, but the score proved scant consolation.
Scotland raced back for the restart, hoping in vain to turn the tide, only for replacement Josh Strauss to knock on.