Match ends, Aberdeen 1, Ross County 2.
Ten-man Aberdeen lost their grip on third place in the Scottish Premiership after a Billy Mckay double earned Ross County victory at Pittodrie.
Derek McInnes' side looked set to end a five-game winless home run when Curtis Main directed in Sam Cosgrove's header.
But teenager Dean Campbell was shown a second yellow card just after the half-hour mark for impeding a free-kick.
Mckay headed in before the break, then squeezed in a late winner to move County eight clear of 11th place.
Aberdeen slip to fourth and are now a point behind Motherwell, who drew with Hamilton Academical.
A first away victory since 21 September helps ease County's relegation fears, with the Dingwall side now having a cushion over the bottom three.
Mckay shows how it's done
"Both the lads are capable of playing together," said McInnes before the match and all eyes were on how the strike partnership of Main and Cosgrove would fare.
It was not long ago Aberdeen were in the midst of a goal drought, but suddenly a deluge - eight in three games going into this - and the twin partnership up top would surely add to that.
From a corner, Cosgrove nodded down and there was Main two yards out to swipe the ball home. He could not miss but the important thing was the partnership was up and running.
But then things turned as young midfielder Campbell - earlier booked for obstruction - earned a second yellow card for sticking out a leg to block a Ross County free kick. It was silly and a bad mistake as Aberdeen were reduced to 10 men.
Right before half time, County would make the hosts pay. Former Aberdeen defender Richard Foster's cross was expertly headed home by Mckay.
Then came a fantastic double stop from Joe Lewis as the second half began with action at both ends. A terrible back pass from Scott McKenna allowed Mckay in, but Lewis blocked his effort. Lee Erwin should have done much better with the follow up but Lewis saved again.
Play immediately swung up the other end as Lewis Ferguson crashed an effort off a post and, from the follow up, Niall McGinn fired in a shot which Ross Laidlaw tipped superbly over the bar.
Lewis would make an even better save to keep out a deflected effort from Josh Mullin, but better was to come from County.
Mckay was played through and the former Inverness Caledonian Thistle forward continued his hot streak by finishing superbly past Lewis to make it 2-1.
Man of the match - Billy Mckay
It's fair to say Mckay has struggled to replicate the highs he enjoyed in that breakout season at Inverness but will he be the man who saves Ross County from any real relegation struggle?
He looks so sharp and took his goals so well. He has five goals in four games and if that form can continue it will be massive for County.
'It was a sore one' - reaction
Aberdeen manager Derek McInnes: "It was a sore one. It wasn't so much that we were hanging on because I didn't think County battered us when we went down to 10 men.
"I'm just disappointed with the manner in which we won't have a point. The last goal was no pressure on the ball and tired minds and tired bodies out there."
Ross County co-manager Steven Ferguson: "It's a big win for us because we realised we needed to right a wrong regarding our away form and to pick Pittodrie as the place to do it was very difficult.
"We need to try and use this as a springboard to make sure that we can get enough points to make sure we're playing Scottish Premiership football next year."
- 18McLennanSubstituted forKennedyat 59'minutes
- 24CampbellBooked at 32mins
- 10McGinnSubstituted forHedgesat 76'minutes
- 16CosgroveSubstituted forMcGeouchat 83'minutes
- 5MorrisBooked at 21mins
- 24PatonSubstituted forSpittalat 71'minutes
- 9MckaySubstituted forDraperat 89'minutes
- 8ErwinSubstituted forShawat 82'minutes
- Gavin Duncan
- Shots on Target
Second Half ends, Aberdeen 1, Ross County 2.
Callum Morris (Ross County) wins a free kick in the defensive half.
Foul by Curtis Main (Aberdeen).
Substitution, Ross County. Ross Draper replaces Billy Mckay.
Goal! Aberdeen 1, Ross County 2. Billy Mckay (Ross County) left footed shot from the left side of the box to the bottom right corner. Assisted by Don Cowie.
Substitution, Aberdeen. Dylan McGeouch replaces Sam Cosgrove.
Substitution, Ross County. Oli Shaw replaces Lee Erwin.
Attempt missed. Blair Spittal (Ross County) left footed shot from outside the box misses to the left following a corner.
Corner, Ross County. Conceded by Joe Lewis.
Attempt saved. Josh Mullin (Ross County) right footed shot from outside the box is saved in the top centre of the goal. Assisted by Billy Mckay.
Attempt missed. Billy Mckay (Ross County) left footed shot from the left side of the box is close, but misses to the left. Assisted by Iain Vigurs.
Substitution, Aberdeen. Ryan Hedges replaces Niall McGinn.
Foul by Callum Morris (Ross County).
Sam Cosgrove (Aberdeen) wins a free kick in the attacking half.
Foul by Billy Mckay (Ross County).
Matthew Kennedy (Aberdeen) wins a free kick in the defensive half.
Substitution, Ross County. Blair Spittal replaces Harrison Paton.
Foul by Billy Mckay (Ross County).
Lewis Ferguson (Aberdeen) wins a free kick in the attacking half.