Manchester City did enough to see off Brighton and reach the FA Cup final on Satuday.
Pep Guardiola's side were nowhere near their best but a largely undistinguished contest was settled by Gabriel Jesus' stooping header after only four minutes, converted from Kevin de Bruyne's perfect right-wing cross.
Brighton battled manfully but could not turn possession into prolonged threat, although City were grateful to Aymeric Laporte's clearance from right under his own crossbar after the break with Glenn Murray poised to score.
City will now face either Watford or Wolves in the final at Wembley on 18 May and also remain in the hunt for the Premier League and Champions League after winning the Carabao Cup.
Guardiola said: "It was a semi-final, Brighton are an incredible defensive team, we knew that set pieces were huge, massive. We conceded too many but only one dangerous situation. We are in the final, we are there.
"My opinion is that nobody has done it [won the quadruple] so why can we do it? It is almost impossible to achieve everything, that is the truth. Our fans will come, more than today, for the final, we are losing players every game but still we will try to do it.
"I am happy to be in the final, we extend our season by one more week and we are happy for that."