Chelsea overcame an outstanding display by Reading goalkeeper Marcus Hahnemann to take their place in the quarter-finals of the Carling Cup.
Jimmy Floyd Hasselbaink's 58th minute strike was enough to send Chelsea through after the giant American keeper had provided a seemingly unsurpassable barrier.
The USA international produced a string of superb saves in a one-sided match to make life difficult for the Premiership leaders.
But there was little he could do about Hasselbaink's winner, the Dutchman stroking the ball home after Hernan Crespo had teed him up in front of goal.
That strike came as some relief to the visitors, whose frustrating evening began to take its toll on aggravated manager Claudio Ranieri.
The Italian coach saw Hahnemann begin his defiant show as early as the third minute when he blocked Crespo's long-range effort with his legs.
Frank Lampard was denied twice and fellow England midfielder Joe Cole was also kept out by the big keeper, but he seemed to save his best for Crespo.
The Argentinian striker saw a low shot pushed round the post midway through the first half and then saw a header brilliantly kept out by Hahnemann nine minutes before the break.
And when Crespo did finally find a way past the keeper, he remained out of luck as a brilliant dummy and shot from the edge of the area smashed against the edge of the post before rolling along the goal-line and to safety.
Reading provided stubborn resistance and had their moments, gangly striker Bas Savage seeing a deflected header superbly palmed away by Chelsea keeper Neil Sullivan.
And it was ironic that when Chelsea finally found a way through it followed one of the home side's best chances of the game.
Nicky Forster and Andy Hughes both swung at the same shot as Chelsea's defence offered a glimpse of a chance, and the visitors were quick to punish the mix-up as they broke upfield to allow Crespo to lay an inviting pass into the path of Hasselbaink who could hardly miss.
The gutsy home side were desperately unlucky not to level 11 minutes from time when defender Ivar Ingimarsson's header from Kevin Watson's corner was nodded off the line by Lampard.
But, fittingly, the last word went to Hahnemann who brilliantly palmed over a late long-range strike from substitute Adrian Mutu.