Aberdeen surely kissed goodbye to any already distant lingering Premiership title hopes with defeat and a nightmare performance against St Johnstone.
A free-kick from David Wotherspoon gave Saints the lead and Steven MacLean got a touch to Steven Anderson’s header to add a second before half-time.
Liam Craig polished off the win with a third as the Pittodrie side produced a shambolic show of defending.
It was a spirited display by the hosts, who leapfrog Motherwell into fourth.
However, it is hard to underline just how sloppy the Dons – whose fans in the crowd of 3,990 booed them off – were at the back – and, for that matter, the middle and the front.
Dons deflated and defeated
But for a mysterious decision by referee Craig Thomson to disallow a seemingly legitimate goal it could have been even worse for the visitors.
This was perhaps Aberdeen’s worst performance of the season. There were 87 minutes on the clock before they forced a save from Saints goalkeeper Zander Clark.
It was – to the day – the third anniversary of Dons manager Derek McInnes’s first game in charge of the club and he used the opportunity to give a debut to young right-sided centre-back Michael Rose in place of the injured Ash Taylor.
But he had a tortuous start to his first-team career.
Saints had a golden chance to take the lead when former Dons player Joe Shaughnessy rattled the bar with a header from a corner. The defender should really have buried the opportunity.
However, there was only a short delay in the home side taking the lead.
Wotherspoon curled a free-kick over the wall after a Rose foul. It was a fine strike but Dons goalkeeper Scott Brown looked slow getting down to his right side.
It was a goal that was worthy reward for Saints’ first-half efforts. They were totally in command, while Aberdeen were all over the place and so too was another Craig Thomson refereeing decision with 34 minutes gone.
Wotherspoon took a corner on the left, Brown went down like the victim of a sniper among a bunch of his own players and the ball fell to Anderson, who bundled it home.
But, mysteriously, Aberdeen were awarded a free-kick and the goal was chalked off, despite there being no apparent challenge on the goalkeeper.
The blunders just kept on coming. A harmless looking ball was floated towards the far post and Anderson knocked it back towards goal. Brown was flailing again as MacLean claimed the slightest of touches to carry the ball over the line.
Barry Robson replaced young Rose and abbreviated his debut as he reorganised his back line, but it made no difference.
Mark Reynolds lost possession to Graham Cummins, who played in the unmarked Craig to finished with aplomb.
Aberdeen, along with their championship chances, were dead and buried, with Robson’s late free-kick their only real effort at goal.
Celtic, who face Ross County on Sunday and now need two wins for a fifth straight title, can prepare their celebration party.