Aberdeen earned a first win in three games with a surprisingly comprehensive Scottish Premiership victory over in-form Motherwell.

Stephen Robinson's side had won five of their past six league games to sit comfortably in third. But, after James Scott failed to convert a fifth-minute penalty, a delightful Sam Cosgrove chip gave Aberdeen the advantage.

Further eye-catching second-half goals from Niall McGinn and Zak Vyner at a muted Fir Park ensured an unexpected win for the visitors.

Derek McInnes's side move to within one point of Motherwell, who remain in third place in the division.

Constant, reliable Cosgrove

It was all-change for Aberdeen when it came to team selection, but one thing remains the same - when they need a goal, they can always turn to Cosgrove. He has 15 for the season so far - and five in his past five games. Whatever way you slice it, in these turbulent times, he's one constant you can always take for granted.

What wasn't at all easy to predict, however, was the quality of his deft lob, lifting the ball exquisitely over the on-rushing Mark Gillespie in the Motherwell goal. The defence-splitting pass from Greg Leigh was perfect, exploiting the space left by the injured centre-back Peter Hartley. Cosgrove's finish, after a rampaging run through the middle, was simply sublime.

That said, McGinn might argue it wasn't even goal of the day. Gifted the ball by some dithering Motherwell defending, he had plenty to do from just outside the box. Hitting the ball with the outside of his foot - to send it arcing into the top left-hand corner of Gillespie's goal - did the trick nicely.

The Aberdeen fans hadn't had a great deal to cheer about in the previous half dozen league fixtures, in which they had witnessed just two wins. So you can just imagine the volume, and extent, of their celebrations when a third goal arrived. And it was at least as good as the two pearlers which preceded it; Vyner supplied laser-like precision backed with plenty of power from well outside the area to arrow one into the net.

All this, remember, came away from home against a team who had won five out of their previous six matches. All this, despite a line-up which showed five changes from the previous match and in which McInnes could barely field a recognised midfielder.

For Motherwell, a rare bad day at the office, but one which could have turned out altogether differently had they taken their chances. Scott's penalty in the opening few minutes was expertly tipped over by Joe Lewis then, not long after the opener, Chris Long could only strike the outside of a post after being slipped in behind the Aberdeen defence.

That said, the visitors could easily have had more than three. Andrew Considine thought he had netted number four when his header connected with Dean Campbell's corner, only to watch his effort fly inches wide. Then, five minutes from the end, a good stop from Gillespie denied Vyner his second following a real scramble in the box.

Devante Cole's cameo appearance near the end nearly gave the few remaining home fans something to cheer, but Lewis twice saved well from the Englishman to preserve his clean sheet and send the visiting supporters away wondering if a real corner has been turned in Aberdeen's season.

Man of the match - Sam Cosgrove

For one of the best, most delicate finishes you'll see all season - and for leading the line superbly all afternoon - Cosgrove gets the award. No player in red had a bad game but his goal, link-up play and movement were all top notch.

A constant pain for the Motherwell defenders, to whom he didn't give a minute's peace, the Englishman added to his growing reputation as a goalscorer with number 15 of the season so far. His wonderful chip also knocked the stuffing out of a side who'd started very well and missed an early penalty.

'We looked like a young squad' - reaction

Motherwell manager Stephen Robinson: "We haven't got carried away when we've won games and we're not going to get too down now that we've lost. We're still in third place and we'll go again.

"We're a young squad and at times in the second half I thought we looked young. Three young boys made mistakes today and they got punished for it but they're the life and soul of the football club so we'll put an arm around them, pick them back up again and hopefully they'll respond to that."

Aberdeen manager Derek McInnes: "After Joe [Lewis'] save we only got better. We counter-attacked brilliantly, we looked brilliant throughout. We kept a team who are going great relatively quiet.

"Obviously, I'm very pleased with the clean sheet and pleased we scored three and could have scored maybe one or two more. By and large it was a very good team performance."