Jason Roberts struck in the last minute of extra-time to send Wigan Athletic into the League Cup final, a 2-1 defeat at Arsenal on Tuesday putting the underdogs through on the away goals rule after a 2-2 aggregate scoreline.
Twice former winners Arsenal looked on course to advance after substitute Robin van Persie netted a spectacular free kick in the 18th minute of extra-time to make it 2-0 after Thierry Henry had headed the hosts into a 1-0 lead in the 65th.
But Roberts, who had earlier missed half a dozen chances, broke clear in the 119th minute, forced his way past two defenders and kept his cool to tuck the ball home and send Wigan into their first major final.
Juan Antonio Reyes had a penalty saved by Mike Pollitt in the 22nd minute and the Wigan keeper made several more good saves to keep the visitors in what was a pulsating, action-packed second-leg game.
While Roberts was celebrating his goal, many of his team mates and many of the travelling fans were preparing for penalties, unaware the away goals rule applied.
"A few of the boys didn't even know we'd won, they thought it was going to penalties, I knew we had," Roberts told Sky Sports.
Wigan were elected to the Football League in 1978 and are enjoying an excellent first season in the top flight. They are currently in sixth position in the Premier League, behind Arsenal on goal difference.
They have never previously gone beyond the quarter-finals in the FA or League Cup.
"Twenty eight years ago we were playing non-league football and now we are in a cup final," said Wigan chairman Dave Whelan.
ABSOLUTELY FANTASTIC
"I didn't realise it was the away goals rule either but its absolutely fantastic for the whole of Wigan."
Arsenal manager Arsene Wenger, who always fields weakened teams in the League Cup, which he has never won, used Henry in the competition for the first time since 1999.
The French striker earned the penalty that should have put his side ahead when his cross was handled by Stephane Henchoz.
Reyes took the kick and it was well saved by the diving Pollitt, making the Spaniard the fourth Arsenal player to miss from the spot in regulation time this season.
Wigan had three penalty claims waved away while Roberts missed good chances either side of halftime.
Pollitt was on his mettle to keep Henry at bay but the Frenchman could not miss, even with his head, when teenage defender Kerrea Gilbert broke down the right and delivered a pinpoint cross.
It was the first goal Wigan had conceded in eight and a half hours of League Cup play this season and it stung them into their best spell of the game.
But the game went into extra-time and van Persie, on as a 79th-minute replacement for Henry, produced a free kick the French maestro would have been proud of, his powerful, dipping left-footer giving Pollitt no chance.
Wigan pushed big defender Paul Scharner up front and it was his determination that opened the way for Roberts to snatch it at the death.
"It's absolutely fantastic," said Wigan manager Paul Jewell.
"Everyone deserves it. The chairman's on the pitch, it's just a fairytale that continues, we've even got a good chance of getting into Europe."
Manchester United host Blackburn Rovers in the second semi-final on Wednesday level at 1-1.
The final is on February 26 in Cardiff.
