Guernsey FC boss Tony Vance says he is frustrated he cannot pick his strongest team when his side travel, meaning his side do not "go away with a momentum".
Guernsey beat Barton 4-0 in the FA Trophy preliminary round on Saturday.
First-half goals from Mark McGrath and Dave Rihoy were added two by a second-half brace from Luke Winch.
"We had a home game and didn't have the work commitments so we were always going to have more of a full quota available," Vance told BBC Guernsey.
But Vance says his side will not be able to play as well on Tuesday when they travel to Tooting and Mitcham United in the Isthmian League Division One South.
"I'm standing on the sidelines and really enjoying the performance, really enjoying the way the lads are deserving to win the game, being ruthless and defending very well.
"But I'm frustrated because on Tuesday night we're going to go with about six of seven players who can't make it.
"That's really annoying because you want to go away with a momentum that you can build, but you know that Tuesday will be a completely different story.
"But that's the frustration of being the Guernsey FC manager."