Hendon joint-manager Motty Korman told JC Sport: "We were 3-0 up inside 25 minutes, but played rest of game with 10 men after having a man sent off.
"We're always in control of the game on a muddy Copthall pitch.
"It was an excellent performance on a tricky pitch and we're into next round of the cup. A job well done."
Faithfold player-manager David Garson told JC Sport: "It was pudding of a pitch at Copthall - the mud was the winner and we all came off grateful we don’t have to wash the kit. Good luck to Hendon in the next round."