Deadlock was broken within the first 10 minutes when Liverpool defender Ibrahima Konaté rose the highest to slam a powerful header from a corner kick.
And the afternoon went from bad to worse for City, as goalkeeper Zack Steffen wanted too much time on the ball, allowing Sadio Mané to slip in and deprive the American national team player of doubling the lead.
And in the battle of the break, Liverpool’s lead was three as Mané flew in at the nearest post, past a desperate Steffen.
Just lost everything seemed for City, Jack Grealish appeared with a goal minutes after the break to give his side hope, and Bernardo Silva pressed from close range in the 90th minute to ensure a nervous finish.
Mané subsequently told the BBC that the day was “special”.
“We played against one of the best teams in the world. Winning this kind of match, especially in a semifinal, is a big, big, big win,” he said.
“We were very happy to win and qualify for the final. We started very well, everyone started on the front foot – for my first goal the goalkeeper made a mistake, but I think we pressured him to make that mistake. It is our style and I think that made the difference. ”
The finest fighters
Red and blue, radiant in the London sun.
Two of the world’s best teams are fighting – a week after their last meeting – for a place in the final of football’s oldest competition.
For neutrals, there could not be a more perfect setting: a packed stadium, beautiful weather and some football stars on display.
With both popping the ball around with a zipper and verve, the first goal came through a more agricultural route.
Liverpool defender Konaté continued his rich spirit of goal-scoring form as he sent a header home from his side’s opening corner of the match – his third goal in as many matches.
The goal got Liverpool fans wild, and when City resumed the game, the air was thick with the smell of blaze, the sunlight turning red as Liverpool fans jumped in celebration.
The red end of Wembley jumped for joy just eight minutes later.
When City tried to play out from the defense, as they typically do so well, Steffen – City’s cup goalkeeper – just wanted fractions too long on the ball so Mané could slide in and tackle the ball home.
The moment bore striking similarities with their clash in the Premier League last week, with regular starter Ederson also grabbing the ball but was just able to nod the ball away in time in front of the forward striker.
Shell-shocked over two goals, Manchester City were finally able to gain a foothold in the showdown as the reigning Premier League champions pressed for a return to the match.
But that pressure left room for Mané to take advantage of to further extend Liverpool’s lead right at the break.
Somewhat complicated play between Liverpool’s strikers put an opening on the squeeze for the Senegalese star to slam the ball home without Steffen getting any chance.
Liverpool flourished and probably did not want the break whistle to come when it happened.
And with manager Pep Guardiola’s words ringing in his ears, City got off to a much improved start to the second half.
English national team player Jack Grealish sent his finish into the top corner after Gabriel Jesus opened up for a shooting opportunity.
The goal brought to life the City players – and the fans – after a bad opening in 45 minutes, where their attack looked much more threatening.
Jesus could have pulled City to within just one goal as his well-timed run got him through on goal, only for his Brazilian team-mate Alisson to deftly refuse him.
Although Man City pressed on, it was actually Liverpool who had the best chances, with Mohamed Salah unable to convert any of his attempts.
Just when all hope seemed to be lost, left an excellent touch and ran from substitute Riyad Mahrez Silva with the easiest finish to leave City behind with just one goal with four minutes left of extra time.
Raheem Sterling had a chance to score against his old club and be the hero with one of the last touches of the match, but could only shoot directly at Alisson.
And despite some chaotic scenes in the City box, Liverpool were able to hang on and advance to the final, ensuring that a historic quadruple – the Premier League title, the Champions League, the FA Cup and the League Cup – is still possible . .
So far, Liverpool have already won the League Cup title, are number two in the Premier League – one point behind City – are in the Champions League semi-finals and are now in the FA Cup final.
When Mané was asked if the quadruple is their wish, Mané said it was a “dream”.
“We have a lot of fights left and we will try to do our best – it’s definitely our dream and we will fight for it.”