Dani Ceballos scored a dramatic late winner as we booked ourselves a place in the Emirates FA Cup semi-finals at Wembley.
Sheffield United had a goal ruled out by VAR before Nicolas Pepe drilled home a penalty following a foul on Alex Lacazette.
Pepe went close to a second but, after pushing us back in the second half, the home side grabbed an equaliser through David McGoldrick with three minutes left.
Extra time was looming but Ceballos had other ideas and latched onto a loose ball in the box to score from a narrow angle and set up a Wembley clash with Manchester City.