A fourth-minute goal from Gabriel Jesus helped City edge past Brighton 1-0 in their FA Cup semi-final at Wembley to take one step closer to the domestic treble and a first Champions League trophy.
With the League Cup already in the bag after a win over Chelsea on penalties, City will face Wolves or Watford in their second Wembley final of the season on May 18.
City are two points behind Liverpool at the top of the Premier League with a game in hand and face the first leg of their Champions League quarter-final at Tottenham's new stadium on Tuesday night.
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“I am happy to be in the final. We extend our season by one more week and we are happy for that," said Guardiola.
“For the first ten or 15 minutes of the second half, we were worried. After that, no.
"They are dangerous. It was tough. It’s a semi-final; they are incredible defensively; well-organised and we knew that set-pieces were huge for them. We didn’t concede too many – just one dangerous situation.
“We are happy to be in the Final, after winning two titles this season. We are now in the final of the other and in the other two competitions, we are there.
It’s almost impossible to win the quadruple. Surviving is a miracle and it’s nice to be there. My opinion is that nobody has done it so why can we do it? It is almost impossible to achieve everything – that is the truth.
“We are losing players every game with tiredness or injuries but still we will try to do it. It’s incredible what these players have done so far, and we are going to try and win every game until the end.
“Today, we didn’t ‘conserve energy’. If it’s 3-0 of 4-0, then fine – but this was absolutely open until the referee said it was the end."
Guardiola believes City are on course for glory because they are an honest group of players.
“When you achieve 100 points, you cannot repeat that. The following season, there is a tendency to be arrogant but we are still there," he said.
No team can perform fantastically for every single game. Sir Alex Ferguson won the treble with United and not every game was like that. It doesn’t work in that way. The important thing is that we have won two titles this season and we are second in the Premier League. We did it.
"I first have to live (winning the FA Cup) before I can tell you how it will feel for me personally!"
"I don't know what condition we will arrive to the final in, but we are happy to be there."
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