Aberdeen suffered a set-back in the race for third and automatic Euro qualification as they crashed 1-0 to Motherwell at Pittodrie.
Third-placed ‘Well extended their advantage over the Reds to four points courtesy of a first-half goal from Liam Donnelly.
Aberdeen were aggrieved when a clear penalty was denied with 10 minutes remaining.
Defender Andy Considine was brought down by a late tackle from Liam Polworth inside the box but referee Willie Collum waved play on.
Aberdeen boss Derek McInnes made two changes to the starting XI that defeated League One part-timers Dumbarton 1-0 in the Scottish Cup fourth round at the weekend.
Midfielder Lewis Ferguson returned from suspension and on-loan Atlanta United attacker Jon Gallagher also came in, with Bruce Anderson and Connor McLennan dropping to the bench.
Aberdeen created the opening opportunity in the sixth minute when Ash Taylor met a Niall McGinn corner but the centre-back blazed a header over the crossbar from 12 yards.
In the 19th minute Motherwell came close to breaking the deadlock when Christopher Long’s low drive from an acute angle was parried across goal by keeper Joe Lewis.
Right-back Shay Logan stuck out a leg to clear in front of an open goal and his clearance hit Allan Campbell on the face and deflected over the bar.
Moments later the Dons threatened when Logan’s cross from the right was headed on by Sam Cosgrove in the box towards Considine at the back post.
The defender’s stabbed volley from six yards was blocked by keeper Mark Gillespie’s feet, deflecting it wide for a corner.
Motherwell suffered an injury blow in the 31st minute when striker Long appeared to twist his ankle in a fair challenge at the edge of the box from Dylan McGeouch.
Long was replaced by Christian Ilic.
In the 36th minute McGinn fired a shot over from 25 yards.
Motherwell went ahead on the stroke of half-time as the Dons inability to defend a set-piece was punished.
Liam Polworth flighted in a superb free-kick from 35 yards out on the right to the far post.
Liam DONNELLY raced in front of Shay Logan and was allowed a free header which he powered beyond Lewis from six yards.
It was the final act of a half where Aberdeen lacked width and attacking edge. Sections of the Dons support made their frustrations vocal by booing.
Aberdeen attempted to force an equaliser with Cosgrove and Taylor both spurning chances in the second half by heading over.
In the 73rd minute Cosgrove latched onto a corner from McGinn but his header was straight at the keeper.
Aberdeen were denied a clear penalty in the 78th minute when a quickly taken free-kick released Considine into the box.
Declan Gallagher slid in late to the challenge and clearly poleaxed Considine. However, referee Collum waved play on.
McInnes went for it with 10 minutes remaining when taking on attackers Curtis Main and Anderson for defenders Logan and Taylor.
In the 85th minute Cosgrove fired in a shot from a tight angle but keeper Gillespie saved as Aberdeen’s frustrations in front of goal continued.
There had been cheers throughout the entire 90 minutes from the Red Shed in the weekend’s Scottish Cup tie against Dumbarton.
At an eerily quiet Pittodrie, there were only deserved boos at full-time.
ABERDEEN: Lewis, Logan, Taylor, McKenna, Considine, Ojo, McGeouch, Ferguson, McGinn, Gallagher, Cosgrove.
Subs: Hedges (for Ojo 69), Main (for Logan 80), Anderson (for Taylor 80)
Subs not used: Cerny, Devlin, Campbell, McLennan.
MOTHERWELL: Gillespie, Hartley, Gallagher, Carroll, Grimshaw, Donnelly, Campbell, O’Hara, Scott, Polworth, Long.
Subs: Ilic (for Long 31), MacIver (for Scott 70), Mugabi (for Ilic 75).
Subs not used: Carson, Seedorf, Ndjoli, Tait.
Referee: Willie Collum