Pedro’s extra-time winner gave Chelsea victory at Leicester City to set up an FA Cup semi-final date with Southampton at Wembley.
Antonio Conte’s side dug deep after the midweek Champions League defeat in Barcelona to keep their hopes of silverware alive as they survived an attacking assault from The Foxes.
Alvaro Morata took Willian’s pass in his stride to beat Leicester keeper Kasper Schmeichel in composed fashion to give Chelsea the advantage just before half-time.
But Jamie Vardy made amends for a poor headed miss when he pounced in a goalmouth scramble for a 76th minute equaliser.
The decisive moment came just just before the interval in extra time when Chelsea substitute Pedro beat the onrushing Schmeichel to N’Golo Kante’s cross and headed in the winner.
Chelsea will play the Saints – who reached the last four by beating Wigan earlier on Sunday – on either 21 and 22 April at Wembley.
Manchester United and Tottenham Hotspur, who won their respective quarter-finals on Saturday, will contest the other tie.
Chelsea manager Antonio Conte’s hopes of silverware this season – which increasingly looks like it will be his last at Stamford Bridge – rested entirely on this game after the Champions League exit to Barcelona.
And how superbly Conte and his players responded to that disappointment, as tired bodies and minds managed to keep their FA Cup aspirations on track in the face of Leicester’s relentless effort.
Chelsea looked to have lost momentum when Vardy scrambled home The Foxes’ equaliser 14 minutes from the end of normal time to ensure this compelling quarter-final would go the extra distance.
But Chelsea showed renewed character, resilience and quality to disappoint a typically fervent home support and demonstrate some of the old steel that brought Premier League title success in Conte’s first season.
Conte was, as usual, the driving force from his technical area, and the nature of this performance (and indeed the display in defeat in the Nou Camp) was proof that, despite all the uncertainty surrounding his future, these players are still performing for their manager.
He also retains the faith of Chelsea’s fans, who chanted Conte’s name loudly in their corner of the King Power Stadium. The manager repaid their loyalty with an outstanding victory.