It was a frustrating afternoon for Motherwell fans as individual errors cost them dearly in a 3-0 home defeat to Aberdeen.
Stephen Robinson made just one change from the team that beat St Mirren 2-0 before the International break with Devante Cole doping to the bench and Chris Long coming in.
Aberdeen meanwhile started the game without a recognised centre midfield player with defenders Zak Vyner and Greg Leigh forming a partnership in the middle of the park.
Both sides had chances from outside of the box early on with Cosgrove striking for the visitors and James Scott for Motherwell but both were easily saved by the respective goal keepers.
Then, just five minutes, Motherwell had the opportunity for the dream start when Chris Long went down inside the area after an apparent trip from Dons keepr and captain Joe Lewis.
The big Englishman was adamant he hadn't made contact but referee Euan Anderson would not be dissuaded and awarded Motherwell the penalty kick.
Up stepped Jame Scott who hit the ball with power to the keepers right but it was just too central and Lewis was able to get a strong hand to the ball and divert it over the cross bar.
Even at such an early stage in the game this seemed to put the momentum firmly in Aberdeen's corner and it wasn't long before they were in front.
Motherwell were temporarily reduced to ten men with captain Peter Hartley forced off after taking the full force of a James Wilson shot to his face.
Well were forced in to taking no chances and replacing him with Bevis Mugabi.
Barry McGuire dropped back to centre half and it was a long ball over the top from Greg Leigh, after Well had conceded possession in the middle of the park, that picked out Same Cosgrove who ran in on goal from the right channel before gracefully chipping it over the top of the advancing Mark Gillespie and in.
It was a nightmare opening 15 minutes for the Steelmen after missing the penalty, losing their captain to injury and then conceding the opening goal.
The first half then wen't on with little to shout about for Motherwell - their best opportunity coming from a mix up at the back for Aberdeen which saw Chris Long hit the outside of the post from a tight angle inside the area.
Motherwell looked to start the first half positively but they were 2-0 down after 53 minutes as Niall McGinn picked the ball off of Richard Tait in the Mother well half, took the ball to the edge of the box and fired a unstoppable shot 20 yards in to the far corner leaving Gillespie no chance.
The match was efectivley ended as a contest on 61 minutes when makeshift midfielder Zak Vyner worked himself a bit of space on the edge of the Motherwell box and hit a low, hard drive that hit off the inside of the far post and in with Gillespie once again helpless to prevent the goal.
It was three quality finishes from the Dons but, frustratingly for Motherwell, all three goals came from conceding possession too cheaply.
Motherwell never really looked like scoring after that with the exception of late shot from Devante Cole which forced a diving save from Lewis on 85 minutes.
Aberdeen also had chances to extend their lead but 3-0 was the final scoreline on a dissapointing afternoon for the Steelmen.