Second-tier Inverness Caledonian Thistle booked a place in the Scottish Cup semi-finals as they came from behind to stun top-flight Kilmarnock.
The visitors burst out the traps thanks to a deft Kyle Vassell touch at a corner inside three minutes, but Billy Mckay’s penalty restored parity.
Skipper Sean Welsh drilled in the hosts’ winner with a 25-yard strike ghosted through goalkeeper Sam Walker.
Kilmarnock join Livingston on Inverness’ list of scalps this season.
Billy Dodds’ side can now look ahead to a date at Hampden next month and will learn their last-four opponents in Monday night’s draw.
The Inverness manager revelled in his team’s achievement, saying: “I was quite calm. I trusted my players. I thought we were the better team. Kilmarnock put us under pressure with long balls in the second half.
“But I just stood back and enjoyed watching my players. I would like a shot in the Premiership – a lot of my players could do it.
“If you do it [beat a top-flight side] once, people say it’s a one-off. But if you do it two or three times, it’s self explanatory.”
After highlighting Kilmarnock’s set-piece prowess prior to kick-off, Dodds will have felt frustrated as his side let the visitors score from their first of the evening.
Danny Armstrong floated in a corner that ricocheted off Inverness midfielder David Carson, before brushing Vassell for the striker’s second successive goal in the competition.
The Highland hosts, though, launched into a roaring response. Welsh was at the heart of things for Inverness, prodding into the ball into the path of Mckay for an improvised header saved well by Walker, before watching his effort skim the crossbar after a sizzling cross from Jay Henderson.
A deserved leveller arose after Wallace Duffy’s delivery struck the arm of Joe Wright in the box, allowing Mckay to send the penalty straight down the middle in composed fashion.
Kilmarnock’s inability to get a foothold in the game almost allowed for a quickfire double when Henderson found himself in behind, but a feeble finish was gathered by Walker.
Stramashes in the box seemed the Ayrshire club’s only route towards regaining the lead, with half-chances for Christian Doidge and Vassell before the interval.
As snow began to fall at the start of the second half, a hot start from Inverness warmed the home support when Welsh’s long-range strike bounced beyond Walker to give Dodds’ side the lead.
The skipper had the chance to double the advantage but failed to meet a fizzing ball across the face of goal from Nathan Shaw.
From there, the game was managed with maturity. Austin Samuels fluffed the opportunity to extend the advantage late on, but Inverness deservedly became the first side through to the last four.
Player of the match – Billy Mckay
Confident Caley Thistle catch Kilmarnock cold – analysis
Uninitiated onlookers would be forgiven for thinking Inverness were the top-flight side in this one, such was the disparity between them and their blunt opposition.
There was zip and vigour in the Highlanders’ play, swirling around Kilmarnock like the blizzard that was engulfing the Caledonian Stadium in the second period.
Derek McInnes’ men, meanwhile, were ice cold. The early lead turned from a dream start to a nightmare as the Premiership strugglers looked caught in the headlights.
Unable to impose themselves on Inverness in any meaningful way, McInnes must desperately look for solutions if they are to spare themselves a rapid return to the second tier.
What they said
Inverness CT manager Billy Dodds: “I had a hug with the chairman (Ross Morrison) afterwards, it was his birthday.
“I told him to enjoy the Livingston game and then I told him to enjoy tonight – and I’ll tell him to enjoy the semi now too.”
Kilmarnock manager Derek McInnes: “I’m really disappointed. I expected more from the team. We got off to a good start.
“I thought from there on in, we stopped playing. We got too complacent and made too many errors.”