Tony Vance has criticised Guernsey FC for failing to take their chances in the 2-1 loss at East Grinstead Town.
The defeat leaves Guernsey 13th in Isthmian League Division One South, 11 points off the play-off places.
"We were dominant in the first 30 minutes and the game should have been won," Vance told BBC Radio Guernsey.
"But our inability to finish off chances, trying to score the perfect goal and not getting our shots off at the right time has probably cost us."
The Green Lions have lost eight of their last 10 games, including seven successive away defeats, but were a goal ahead early on Easter Monday.
"I'm more disappointed with the way we let them off the hook," added Vance. "People talk about the first goal being important, but the second goal is even more important.
"We got that first goal, which we deserved, and we had so many opportunities to get more again.
"Even in the first 15 minutes of the second half we had so many chances and were totally dominant, but we didn't take them.
"Lo and behold we find ourselves 2-1 down, but they were battling and fighting for their lives and any time they were in with a shout they were going to take something and they did."