Aberdeen’s disappointing form continued as they crashed 1-0 to St Johnstone at Pittodrie.
The Reds lost out on the chance to move level on points with Motherwell in third after the Steelmen slumped to a 4-0 loss to league leaders Celtic.
It was the fourth successive game Aberdeen have failed to score.
The Dons have now taken just three points from the last five Premiership games.
Their lack of fire power will be a major concern ahead of Saturday’s home Scottish Cup clash with Kilmarnock.
Aberdeen fell behind to an early goal from Ali McCann and then suffered another blow when centre-back Ash Taylor had to come off through injury.
Venezuelan international right back Ronald Hernandez made his Dons debut having been an unused sub in the 0-0 draw at Rangers on Saturday.
Signed on a four-and-a-half year deal from Stabaek Hernandez has not played competitively since the Norwegian season finished on December 1.
However the transfer deadline day signing was involved in a recent pre-season with Stabaek and was pitched in from the start against Saints.
Hernandez was one of three changes Aberdeen boss Derek McInnes made to the starting XI that held Rangers.
Returning to the starting line up were Ryan Hedges and on loan Atlanta United attacker Jon Gallagher.
Right back Shay Logan, Funso Ojo and Niall McGinn dropped to the bench.
January signing Matty Kennedy made his Pittodrie debut when going up against former club St Johnstone.
Kennedy had initially agreed a pre-contract to join the Dons in the summer from Saints but the Dons pushed through a move during the winter window.
Aberdeen created the opening opportunity in the third minute when Ryan Hedges picked out Jon Gallagher inside the penalty area and the on loan Atlanta United attacker slammed a low 12 yard drive into the side netting.
Within the first five minutes Hernandez superbly dispossessed David Wotherspoon before going on a run where he attempted a step over and turn.
However Aberdeen went behind in the sixth minute when Liam Craig released Ali McCANN with a pass that completely exploited an Aberdeen back-line stranded out of position.
McCANN raced at goal and lifted the ball above Joe Lewis as the keeper went to ground.
Aberdeen suffered another blow when centre-back Ash Taylor was forced off injured in the 20th minute to be replaced by Scotland international Mikey Devlin.
The Reds came close in the 32nd minute when Scott McKenna met a corner whipped into the near post by Matty Kennedy but the centre-back’s powerful header from six yards flashed just wide.
In the 43rd minute Hedges unleashed a powerful half volley on the turn from 20 yards only to be denied by keeper Zander Clark who punched clear.
It was Aberdeen’s first shot on target – at home.
The Red Army made their frustrations clear at half-time by booing the flat Dons.
Boss McInnes attempted to rectify the situation at half-time and introduced Northern Ireland international Niall McGinn for Gallagher.
In the 50th minute a driving run from Kennedy had Saints on the back-foot and the winger found Cosgrove with a pass but the leading scorer’s effort was blocked by the foot of keeper Clark.
Soon after substitute Niall McGinn flashed an inviting cross along the face of goal from the left flank but there were no takers.
Aberdeen controlled possession but struggled to make it count.
In the 77th minute Hedges played a short free-kick to McGinn who found McKenna in the box with a curling cross.
The defender’s effort was saved by keeper Clark and Cosgrove failed to capitalize from the rebound.
Aberdeen were denied a point in injury time when Niall McGinn curled a 25 yard free kick over the defensive wall only to see it crack off the inside of the post.
The Dons left to boos from the frustrated Aberdeen supporters.
ABERDEEN: Lewis, Hernandez, Taylor, McKenna, Considine, McGeouch, Ferguson, Gallagher, Hedges, Kennedy, Cosgrove.
Subs: Devlin (for Taylor 20), McGinn (for Gallagher 46),
Subs not used: Cerny, Logan, Campbell, Ojo, Anderson.
ST JOHNSTONE: Clark, Ralston, Booth, Kerr, McCart, Craig, McCann, Holt, O’Halloran, Wotherspoon, Stevie May.
Subs: Wright (for O’Halloran 26), Kane (for May 60),
Subs not used: Parish, Duffy, Hendry, Butcher, Jones.
Referee: Kevin Clancy