Powerhouse Tykes striker Kayode Odejayi delivered the holders a sensational knockout blow, rising highest to head home Martin Devaney's superb cross in the 65th minute for the only goal in a thrilling 'David versus Goliath' quarter-final at a sold-out Oakwell.
But the Israeli and his captain were gracious enough in defeat to pay tribute to Coca-Cola Championship side Barnsley and their fairytale cup run. Simon Davey said of his opposite number: "He just said 'well done'. He was very sociable. He's a nice fella.
"John Terry came up to me at the end of the game and said 'go on and win it, you deserve it after today'.
"So it's great to have people of that stature in the game saying that afterwards."
Davey, who never played above League One level as a player, admitted he and his players were in "dreamland" after trumping their memorable win at Liverpool in the previous round.
"I never thought the Anfield win could be eclipsed and today, in front of our own fans, against mighty Chelsea with all their millions, we've done it and I couldn't believe it.
"I still can't believe it now and hopefully I'll wake up in the morning and it will still all be true."
Chelsea a took command early in the second half and it appeared their extra class would tell, but just when Barnsley legs appeared to waver, Delaney swung over a top-class cross and Odejayi thumped home his decisive header.
Davey added: "You have to enjoy days like these. It was a big day for Barnsley and a big day for the players and they went out to enjoy the game.
"Nobody was found wanting. Everyone put a shift in and they've come up trumps again.
"To go to Anfield and win and then to go and beat Chelsea in the same season is a fantastic achievement and my players deserve a lot of praise."