Pedro goes the extra yard
Leicester 1 Chelsea 2 (after extra time)
Chelsea provided the FA Cup shock. It was not that they won this fiercely contested quarter-final - but that the decisive goal came from a header by substitute Pedro Rodriguez: all 5ft 6in of him. The little man rose to the occasion with the big moment.
Having spent the January transfer window searching for a tall target man, Antonio Conte was saved by the aerial prowess of the smallest player in his squad. When Pedro scored in extra time, the Chelsea head coach already had Olivier Giroud - the striker the club ended up buying - ready to come on to replace their other centre-forward, Alvaro Morata.
Reaching an FA Cup final will not define Conte's future, of course, but given the sense at Chelsea is that he will leave at the end of this campaign, it remains possible that he will do so with a trophy.
Chelsea fans, who were in fine voice here, sang of going to Wembley - where they will face Southampton in the semi-finals - and chanted Conte's name. Whatever the level of upheaval, there is no question that this team are not playing for their manager.
Defeat was hard on Leicester, who made the running throughout this tough encounter, in the numbing cold, while Chelsea should be praised for the way they dragged themselves back from the disappointment of their Champions League exit at Barcelona, to survive two hours of bone-jarringly raw domestic cup football.
The indefatigability of Chelsea was summed up by an extraordinarily energetic performance from N'Golo Kante, who drove them forward in midfield, an area he keenly contested with Leicester's Wilfred Ndidi and Vicente Iborra.
Just how well he played was highlighted by the fact that, again, Tiemoue Bakayoko struggled. On his first appearance since his dismal display and first-half dismissal against Watford, he was taken off at half-time. Conte dressed it up as a precautionary move, given Bakayoko had been yellow-carded, but he clearly did not trust him.
Bakayoko has not been the only Chelsea player who has struggled of late and it looked like this would be another difficult day for Morata.
Roughed up by Wes Morgan and Harry Maguire, the striker appeared increasingly frustrated. He went into this game on a run of 13 games without a goal, having just been left out of the Spain squad, and spurned the first couple of chances that came his way.
But then he scored. It was a superb, counter-attacking goal which came as Riyad Mahrez attempted to beat three Chelsea players on the edge of their own penalty area, with Marcos Alonso nicking away possession. Suddenly, from Antonio Rudiger's pass, Willian - again impressive - surged away from Ben Chilwell and Ndidi before sliding the ball through to Morata, who had smartly pulled away from Morgan.
Morata ran on and bent his side-footed shot up and around Kasper Schmeichel. It was, in keeping with the conditions, an ice-cold finish.
Leicester had taken the game to Chelsea with Marc Albrighton half-volleying wide and Morgan almost connecting at the far post. But it was not until the second half that they began to dominate and only when they could finally get Jamie Vardy involved.
Vardy still sets the tone. After he fluffed his first chance, making a hash of a header when picked out by Ndidi, he was on a mission. Inevitably it resulted in him scoring. Vardy's shot from Mahrez's cross was blocked and then Iborra's first effort was also blocked, with the midfielder forcing an excellent save from Willy Caballero as he stabbed the next rebound goalwards.
The third rebound, though, fell to Vardy and he swept it home although, even then, Caballero got a hand to it.
Ten of Vardy's 17 goals this season have come against top-six sides and, soon after, Leicester almost went in front when he forced another save from Caballero after a strong run by Maguire. At the other end, Morata could have won it as he ran on to Willian's clever pass, only to be denied by Schmeichel with a fine double save.
It meant the tie went to extra time. Chelsea had to cope with the loss of Willian and Andreas Christensen, both to fatigue. Would Leicester capitalise?
Instead, it was Willian's replacement, Pedro, who made the difference as he drifted into space away from Maguire, Chilwell and Albrighton to meet Kante's measured cross. Schmeichel misjudged, hurtling from goal and being left in no-man's land, and Pedro cushioned his header into the net.
A headed goal from Pedro is a rarity, although Leicester had been warned - he had scored his only other header against them, here, last season.
Leicester had also contributed to their own downfall with their poor defending and a rush of blood from Schmeichel.
It proved the difference and both Pedro and Morata, on a freezing day, had come in from the cold.
© Daily Telegraph, London