David Holdsworth insisted his players had "beat themselves" after a rampant Grimsby Town gave Lincoln City the Boxing Day blues yesterday.
The Imps boss watched on as the promotion-chasing Mariners stormed to a 4-1 victory at Sincil Bank to remain top of the Blue Square Bet Premier table.
But Grimsby were given a helping hand with a mistake from Paul Farman and an Andrew Boyce own goal proving instrumental in defeat.
Holdsworth said mistakes decided the outcome of the fiery encounter as City slumped to their biggest loss at home to the Mariners since 1957.
"We beat ourselves," he said.
"There were too many mistakes and they cost us.
"Paul made an error for the first goal, while Tom Miller should have dealt better with his situation for the second.
"Nobody could legislate for the mistakes we made and from players who would not normally make them.
"While we have been very solid in some games, this was a day the players will want to forget as quickly as possible.
"As you would expect they were extremely disappointed afterwards because they felt they had let the fans down."
Holdsworth refused to criticise Farman for his part in the first goal when he dropped Joe Colbeck's cross which allowed Andy Cook to rifle home.
The former Gateshead stopper apologised on Twitter in the aftermath of the game saying he would "bounce back".
Having been one of Lincoln's best players this season, Holdsworth said Farman was not the only one at fault.
"I do not judge people on just one game," he said.
"Paul has been fantastic for us this season and he is a very good prospect.
"Unfortunately when you are the last line of defence, a mistake more often than not will result in a goal.
"But to be fair he has come in to the dressing room and apologised.
"This is just not about Paul, though because others made mistakes too."
City will now look to make amends on Saturday when they host Gateshead and Holdsworth said he would make changes.
"There will be changes but that is because we have a very busy fixture list and recovery time is short."