Shoreham Football Club manager Sammy Donnelly held his hands up after his side's Bostik League South humbling on Saturday.
Will Hoare, Marcus Elliott and Alex Gaggin all struck twice, while Leo Mazzone also netted as Mussels slipped to a heavy 7-2 defeat at East Grinstead Town.
Mussels boss Donnelly decided to go with a changed 4-1-2-1-2 system to start the game and took responsibility for his team's first half display.
Shoreham were 3-0 down at the break and facing an uphill task to get back in it. East Grinstead netted a further four times in the second to compound a difficult afternoon for Mussels.
Donnelly said: "I take full responsibility for the defeat. Performances have been improving of late but I decided to change the system, which didn't really work.
"We were a bit better in the second but the damage was done by then. I take the blame for the first half, then we were left with too much to do."
Gaggin broke the deadlock on 15 minutes, then Hoare added a second four minutes later.
A difficult half was rounded off for Mussels with Gaggin making it three on the half-hour.
Elliott got his first four minutes after the restart, before striking for a second time on the hour.
Evan Archibald pulled one back for Shoreham after 70 minutes but Mazzone struck ten minutes to restore East Grinstead's five-goal lead.
Hoare rounded off the home side's scoring six minutes from the end - making it seven. Shoreham striker Dan Simmonds got another back two minutes later as it ended 7-2.
Mussels welcome division-higher Bostik League Premier Division rivals Worthing to Middle Road for a Velocity Trophy first-round encounter tomorrow (7.45pm).
Donnelly, who has managed Worthing previously, is expecting a tough test and said: "They (Worthing) have a good, young team and it will be difficult.
"They have struggled so far this season, as have we, so it will be interesting to see who comes out on top."
SHOREHAM: Broadbent; Packer, Timms, Gathern, Whitehead; Hand, Nazala, Goldson, Burton; Archibald, Simmonds. Subs: Myers (Nazala), Tan (Burton), Nayee (Goldson), Quadri, Caplin.