CARDIFF CITY 0-1 NORTHAMPTON TOWN
Parrish (77)
Cardiff lost 1-0 to Northampton at Ninian Park. Welshman Sean Parrish hit the winner despite Northampton being down to 10 men after losing Mark Cooper seven minutes earlier for elbowing Cardiff skipper Jason Perry.
But if Cardiff face a herculean task Swansea go into Wednesday's second leg against Chester at Vetch Field brimming with confidence after a goal-less draw at Sealand Road.
Ian Atkins, who turned down the chance to become Cardiff's manager earlier this season, instead became the man who sabotaged their ambitions.
Atkins, once a defender of crunching renown, has instilled the same brand of well-drilled meanness into a Northampton side who have now conceded just one goal in their last half-dozen games.
'I don't mind if people call us Scrooges - I though our defenders were superb today,' he said.
To compound Cardiff's misery Wrexham born Parrish sent them tumbling to defeat. He struck 13 minutes from the end of a gruelling war of attrition, drifting past two defenders to spot goalkeeper Steve Williams off his line and beat him with a delicately judged chip.
It was the ninth goal of the campaign for the bustling 25-year-old midfielder whose sense of timing was perfectly judged with Welsh manager Bobby Gould watching.
'He came to see me once earlier this season - and I fractured my cheekbone,' said Parrish, a late developer who is in only his third season as a professional.
'I would love to get the chance to play for Wales. I know I have improved a lot over these past three years.'
But such is the strength and organisation Atkins has built into his side that even with their ranks depleted they were rarely in trouble.
Indeed, goalkeeper Andy Woodman was given little chance to demonstrate the skills that have made him a target of QPR - he was not called upon to make a single save.
The only occasion he was beaten came in the final minute, when Cardiff launched a despairing final onslaught only for Scott Young's header to be cleared from the line by Ray Warburton.
'I'm not despondent. This tie is still there to be won. The pressure is all on Northampton now,' said Cardiff's Director of Football Kenny Hibbitt.
But his team will need to equal those words of defiance if Cardiff's dream of their first Wembley appearance for 70 years is not to end in tears.
Swansea, meanwhile, kept their end of the bargain with a battling performance that may not have been elegant, but certainly proved effective.