Lowland League Bo’ness were leading through Kieran Anderson’s 12th minute header from a Reis Peggie cross and looked comfortable until a long ball forward saw Ryan Shanley take advantage of hesitancy in the BUs’ defence to shoot home a leveller.
League 2 City then won it late on with a stunning 20-yard strike from the edge of the box by John Robertson.
“It was a long straight ball that we’ve not dealt with and it’s ended up in the back of the net,” Christie told the Journal and Gazette.
"We didn’t see that coming and there was just a minute until half-time so that was disappointing.
"I thought second half we were marginally the better side but the boy Robertson comes on and scores a great goal, bangs it in from 30 yards. And that was the difference I suppose.
"I expect better. We’re 1-0 up, we’ve maybe been sitting in a bit too much but we lose a daft goal and then we’ve got chances to win the game.
"We’re the more dominant side in the second half so it’s a game we’ve got to go and win.
"We’re not a million miles away from the level of Edinburgh City and League 2 teams. We just seem to have had a lot of defeats by the odd goal this year.
"We need to change that and get winning these games.”
With this weekend’s scheduled league opponents Dalbeattie Star unavailable as they are in league action, Bo’ness have no competitive fixture this Saturday.