More on KentOnline
Steve McKimm admitted he was annoyed and frustrated after Tonbridge Angels 2-0 defeat at East Thurrock in the Ryman League Premier Division semi-finals.
Goals early and late in the first half did the damage, with the second in stoppage-time proving decisive.
McKimm said: "We switched off in vital areas at vital times and it cost us the game.
"I'll stand by that, because until we pushed Jerome Sobers forward and they had a couple of half chances it was a nothing game.
"We have got to take in on the chin, and come back stronger next season."
He added: "It was a game nobody expected us to be involved in, but I felt a little bit annoyed, because we didn't play our normal game.
"All season we have been getting down the line and putting crosses in, including the full backs and filling the box, but it didn't look like we had that in us, and it was a shame."
Charlie Slocombe and Charlie Webster, both injured at Burgess Hill on Saturday joined the Angels lengthy injury list.
McKimm said: "All my subs apart from Laurence Ball were reserve team players, but I am not going to use that as an excuse.
"We didn't defend in the right places and attack in the right places"
Looking at the bigger picture having made the play-offs, after finishing 20th last season, The Angels boss was keen to go all the way and clinch a place in Vanarama National South next season.
"When you get to this far, you want to kick-on.
"If we had managed to get through and win the final, look at all those Kent derbies, big games to be involved in, and the revenue from the supporters which they bring in helps.
"We haven't got a sugar-daddy, but we are a financially stable club , and it would sustain us.
"It wasn't to be, hopefully the fans will stay with us, we'll make a few changes in the summer, and go again.
East Thurrock will host Dulwich Hamlet in the final on Monday, after the South London club won 1-0 at Bognor in the other semi-final.