Aberdeen secured a Scottish Cup semi final place on a day of remarkable drama at Pittodrie as Neil Warnock quite as interim Reds boss just minutes after the victory.
Derek McInnes was looking to extend his flawless record against his former club this season but ended up on the losing side against the veteran who announced he was stepping down.
Killie had come out on top in all three of their meetings with the Dons, claiming a 2-0 win against Warnock's side in Ayrshire last month. But Jamie McGrath, skipper Graeme Shinnie and an own goal from Stuart Findlay secured the Dons a place at Hampden.
It's the third time they have been to the National Stadium this season after losing the Viaplay Cup final to Rangers but will be hoping to go all the way and win the Scottish Cup for the first time since 1990.
The match served as a distraction for Aberdeen's dreadful league form, with last weekend's astonishing 2-1 defeat to St Mirren in Paisley leaving Warnock's men without a win in their games The 75-year-old had overseen just one win from his seven games in charge in all competitions, with four league losses leaving Aberdeen just four points above 11th placed Ross County in the Premiership standings.
Follow all the reaction from the first Scottish Cup quarter final fixture of the weekend in our LIVE match blog.
Key Events
Warnock STEPS DOWN
Just minutes after the full-time whislte, Neil Warnock has dropped a bombshell after announcing that he is stepping down from his role at Pittodrie with immediate effect.
Shinnie left seething after yellow card rules him out of semi-final
The Reds captain is livid that he was booked by John Beaton for simulation despite replays showing that he was fouled by James Balagizi.
Talking points
Record Sport's Scott Burns was at Pittodrie and he's picked out the big talking points from a huge day in the north east for the Dons. READ MORE
Shinnie to MISS semi final
Graeme Shinnie was raging with that late booking which looked incredible hard and it's clear now why he was so unhappy as he will now miss the semi final. The captain is absolutely devastated.
FULL TIME - Aberdeen 3 Kilmarnock 1
And Aberdeen are the first of the eight quarter finalists to make it through to Hampden. It's a huge win for the Dons.
Shinnie booked
Graeme Shinnie is raging after he is wiped out on the edge of the box and the Dons skipper ends up getting a yellow card for protesting. Chants of "Beaton, Beaton get to f***" ring round Pittodrie. So much for a quiet day!
Miovski subbed
After that chance, Miovski's work is done and it's another game without a goal for the Macedonian. That's six games he's gone and when you've scored 22 all season then that's almost a drought! Ester Sokler replaces the striker with Duk also on.
The fourth almost with Aberdeen
Almost a fourth for the Dons there as Jamie McGrath stings the palms of Will Dennis. Bojan Miovski then pounces on the rebound and goes down under a challenge from the Killie keeper but there was no way a penalty was going to be awarded.
Triple change for Killie
Derek McInnes has to do something and he's made three changes with Greg Stewart, Garry Mackay-Steven and James Balagizi all introduced. Can they help the visitors conjure up a late rally to keep them in the competition?
Wily Warnock
Pressure, what pressure? Neil Warnock is a veteran and looks like he'll be getting mesured for his Hampden suit. The Englishman did say he fancied a trophy and he could be picking one up in May.
Goal! The Dons have a third
The Dons have restored their two-goal lead and with just 25 minutes to go it's a huge strike that could send them to Hampden for the third time this season.
Junior Hoilett did well down the left and fed the overlapping Jack MacKenzie and his cross from the left was turned in by Jamie McGrath, albeit it took a deflecton off Stuart Findlay on its way past Will Dennis.
Wright booked
Joe Wright's name is taken for a foul on Killian Phillips and Killie have been dragged into more of a scrap now after starting smartly in the second half. That will suit the Dons.
Strong Arm from Shinnie
Graeme Shinnie clatters into Danny Armstrong and the wide man, after initially soldiering on, is in a fair bit of discomfort.
Shinnie pleads his innocence to referee John Beaton and no action is taken but it would be a blow of the Killie man ends up being forced off. He's trying his best to plah on.
Miovski wasteful
It's been all Kilmarnock in the second half but Aberdeen had a great chance on the break as Connor Barron sends Bojan Miovski racing clear but the Macedonian's first touch was too heavy and that allowed Lewis Mayo to clear the danger.
Killie on front foot
Jack MacKenzie has his name taken by John Beaton for a foul on Danny Armstrong and from the resulting free kick Kelle Roos comes off his line but it's headed behind for a corner.
It's a bright start right at the start of the second half for the visitors.
Restart
And we're back under way in the north east. Can the visitors restore parity and put real doubt in the minds of the Dons?
Half time - Aberdeen 2 Kilmarnock 1
And that's the end of the first 45 minutes. It took a while to warm up but it's been entertaining enough and it's all to play for in the second half.
Polworth tries from distance
Liam Polworth with a lovely first touch to bring the ball under control and shot from distance tests Kelle Roos but it's an easy save in the end from the Dutchman.
If the visitors can get the next goal in this game then it will make things very interesting.
Goal Kilmarnock!
It's game on as the Ayrshiremen are handed a lifeline and it's that man Danny Armstrong who has halved the deficit.
Kyle Vassell did brilliantly down the left and his cross found Armstrong who placed his shot beyond Kelle Roos.
Killie rattled
Derek McInnes couldn't have predicted this against his old club given their perfect record against Aberdeen. Danny Armstrong wastes a good opportunity when he goes for goal but just sends his effort wide. He might have been better trying to pick out Kyle Vassell.
Goal! The Dons double their lead
Wow - it's the Dons skipper who gets the second goal and the Reds are well on course for a return trip to Hampden.
Hoilett's ball into the box was laid off by McGrath into Shinnie's path and he rifles a brilliant shot beyond Will Dennis.
You would hardly believe that Aberdeen have been struggling all season while the visitors have been one of the in-form sides.
Vassell a lucky man
The home fans scream for a yellow card for Kyle Vassell as he pushes Stefan Gartenmann to the ground. But the Killie captain escapes a booking and he's definitely a lucky man.
Killie pile on the pressure
Killie are now getting into their stride but Aberdeen look to break through Junior Hoilett - and Polworth takes him out.
Armstrong then bursts into the Aberdeen box but he just can't get the cross away.
Oh dear Donnelly
Liam Donnelly boots the upright in frustration and no wonder. The Irishman blows a glorious chance to level with a free header from a Killie corner which the ex Motherwell man sends wide.
Wayward Vassell effort
Danny Armstrong has been a Premiership standout and he picks out Liam Polworth with a gret ball and he manages to find Kyle Vassell but the skipper makes a bit of a mess of his attempted effort which is way off target.
Killie pen appeal waved away
Stuart Findlay's cross into the box for Marley Watkins hits off Stefan Gartenmann and the ball bounces up and comes off the Dane's arm. Killie players appeal for a penalty but nothing doing - it deflected of his stomach first and would have been harsh.
Aberdeen dominating
The Dons don't look like a team low in confidence and that has just been summed up by Jack MacKenzie running almost the entire length of the park but he couldn't provide the end product as the Killie defence hustle him off the ball.
Goal! Jamie McGrath opens the scoring
And it's the home side who take a deserved early lead. A long ball forward found Bojan Mivoski as Stuart Findlay stumbled. He set up Junior Hoilett for a shot which was parried into the path of Jamie McGrath and he had the simple task of prodding home.
Good idea from Hoilett
Junior Hoilett attempted a throughball for Killian Phillips but there was jusdt too much on it for the on-loan Crystal Palace man.
It was a nice idea from the Canada international but it didn't quite come off. Aberdeen looking the more lively here with Killie still to settle.
Composure needed
It needs someone to get their foot on the ball. There's been a series of niggling fouls and it's all very stop-start.
Killie also have to be a bit slicker in possession with Liam Donnelly and Liam Polworth both caught on the ball early on.
