Aberdeen lost further ground on league leaders Celtic as summer transfer target Louis Moult smashed a double in a 2-0 defeat to Motherwell at Pittodrie.
The Dons had two bid for striker Moult rejected by the Steelmen in the summer, with the highest £400,000.
Motherwell were holding out for an additional £100,000.
Moult underlined exactly what the Reds missed out on by netting a brace.
It was the second time this season Moult, on 15 goals for the season, hit a double past the Dons having netted twice in the 3-0 defeat of the Reds in the League Cup quarter-final.
Aberdeen now trail leaders Celtic, undefeated domestically in 64 games, by six points.
There were three changes to the Aberdeen side that drew 2-2 at Hamilton before the international break.
Skipper Greame Shinnie was suspended while Greg Stewart and summer signing Stevie May dropped to the bench.
It was the first time May, a £400,000 signing from Preston North End, has been a substitute since his summer move.
Andrew Considine returned to the starting line-up and was handed the captain’s arm-band for a 408th start that took him into sixth place in the club’s all time appearance list.
Also moving back to the starting line up were Greg Tansey and striker Adam Rooney.
As early as the fourth minute Rooney broke in front of Cedric Kipre to meet a Ryan Christie cross but the striker’s flicked shot from close range flew inches wide.
A moment later Christie fired in a shot from the edge of the penalty area that was saved by keeper Trevor Carson.
In a lively start to the match Dons keeper Joe Lewis had to produce two quick fire saves within a minute to deny the Steelmen who had began with real intent.
First he blocked a Liam Grimshaw 15 yard effort then stopped a powerful shot from Andy Rose just 30 seconds later.
Motherwell were looking the more dangerous and Lewis brilliant stuck out a hand to deny a Rose drive in the 11th minute. It was a superb, and vital, block with the Reds looking rattled.
Again the Steelmen threatened when Lewis did well to block a Rose effort that was goal-bound until he managed to get a finger-tip to it.
With the Dons being over-run McInnes switched to three at the back on the 20 minute mark in a bid to get more of a foot-hold in midfield.
Motherwell grabbed the lead in the 42nd minute when prolific striker Louis MOULT yet again punished slack defending from the Dons.
Right-back Richard Tait flighted in a cross and Moult peeled away from his marker to be left with a free header. He nodded back across the face of goal and beyond keeper Lewis who appeared rooted to the spot for his 13th goal of the season.
It was no less than Motherwell deserved. At the half-time whistle there were boos from some of the Red Army, clearly frustrated at what they were again witnessing against Motherwell.
Dons boss McInnes brought on May for Tansey at half-time in a bid to turn the game around.
However it was the Steelmen who went further ahead courtesy of danger man MOULT in the 55th minute.
Chris Cadden burst past Scott McKenna down the right flank and delivered a perfectly weighted cross to the near post.
Striker Moult edged in front of Kari Arnason and rifled home a half volley from close range.
Substitute Scott Wright, on for Gary Mackay-Steven a few minutes earlier, whipped in a cross to the near post in the 73rd minute and May unleashed a shot that was pushed behind by keeper Carson for a corner.
In the hunt for his hat-trick Moult fired a 25 yard free kick over in the 82nd minute.
Aberdeen huffed and puffed in a bid to haul themselves back into the match but they were well beaten.
ABERDEEN: Lewis, Logan, Considine, O’Connor, McLean, Rooney, Mackay-Steven, Arnason, Tansey, McKenna, Christie.
SUBS: May (for Tansey 46), Wright (for Mackay-Steven 70), Stewart (for Rooney 83)
SUBS NOT USED: Rogers, Reynolds, Maynard, Ball.
MOTHERWELL: Carson, Tait, Grimshaw, Hartley, McHugh, Moult, Cadden, Bowman, Rose, Dunne, Kipre.
SUBS Frear (for Bowman 55): Campbell (for Grimshaw 71), Fisher (for Moult 89)
SUBS NOT USED: Griffiths, Tanner, Plummer, Petravicius.
Referee: Bobby Madden.