League Two's Newport County beat former Premier League champions Leicester City 2-1 at Rodney Parade - with Irishman Pádraig Amond's second-half penalty proving decisive.
The Carlow native ensured that County progressed into the fourth-round of the FA Cup, at the expense of the Foxes.
"It's a penalty so you're expected to score. I played with Danny Ward at Morecambe, he faced a few of my penalties in training so I was hoping he wouldn't remember," said Amond.
"It's brilliant to score the winner but just to win is the big one. Everyone's done brilliantly today and I think we fully deserved it."
It was a day of shocks elsewhere, as Fulham lost 2-1 to League Two Oldham, a home loss for Claudio Ranieri's side compounding the Cottagers' below-par league showings.
'The players involved missed their chance,' said Fulham's boss.
'I wanted to see the players who don't play so frequently, but I didn't see the desire, the passion that Oldham players had.'
Barnet also prevailed at Championship high-flyers Sheffield United, where Shaquile Coulthirst's first-half penalty making it a sweet victory for Bees' caretaker manager, Darren Currie. Currie might have an awkward conversation over dinner, however, as his uncle - Tony - is on the board at Bramall Lane.
"I'm so proud, honoured to be leading them the way they performed," said Currie.
"I asked them to play with no fear today and I think they managed to achieve that. They were outstanding."
"It's a job I want, it's the place I want to start. Hopefully today will help me."
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