A goal by Lucas Rodrigues 13 minutes from time settled the semi-final and put Horsham in the final, where they will play Littlehampton Town on a date to be arranged at the Amex in May.
It will come a year after Dominic Di Paola’s side lifted the trophy with a comfortable win over Hastings.
See pictures from the Hornets’ semi-final win – taken by John Lines – on this page and those linked and get the reaction from the camp in the West Sussex County Times, out on Thursday.
1. Horsham beat Brighton U21s in the Sussex Transport Senior Cup semi-final pictures by John Lines (71).JPG
Horsham v Brighton U21s, Sussex Transport Senior Cup semi-final Photo: Picasa : John Lines
2. Horsham beat Brighton U21s in the Sussex Transport Senior Cup semi-final pictures by John Lines (75).JPG
Horsham v Brighton U21s, Sussex Transport Senior Cup semi-final Photo: Picasa : John Lines
3. Horsham beat Brighton U21s in the Sussex Transport Senior Cup semi-final pictures by John Lines (76).JPG
Horsham v Brighton U21s, Sussex Transport Senior Cup semi-final Photo: Picasa : John Lines
4. Horsham beat Brighton U21s in the Sussex Transport Senior Cup semi-final pictures by John Lines (79).JPG
Horsham v Brighton U21s, Sussex Transport Senior Cup semi-final Photo: Picasa : John Lines