Craig Hignett said he was "embarrassed" and "angry" after Hartlepool United were hammered at Stevenage.
Bogey side Boro, who Pools have never beaten had conceded 12 goals in their previous three matches.
But it was Pools who were taken apart, despite been given a dream start by Nathan Thomas's fourth-minute goal.
Tom Pett levelled for the hosts and on-loan striker Tyler Walker, so of Nottingham Forest and England star Des, put Boro ahead before the break when Pools could not clear their lines.
Stevenage, who had started the day 22nd, added four second-half goals through Dean Wells, Walker, Michael Tonge and Matt Godden as Pools crumbled into the Broadhall Way turf.
“It was painful to watch," admitted Hignett.
"That was unrecognisable from the team and we have had words in the dressing room.
"But what can I say after that, it was embarrassing, I'm struggling to find the words to sum it up.
“We go in front and we should push on, I thought Stevenage were jittery having just conceded five last week at Grimsby and after that early goal I thought they could go.
"The start we had was perfect for us.
"But the goals we then conceded were embarrassing, not, two or three, but all six.
"They were all embarrassing , we cannot defend like schoolboys."
Pools had something of a makeshift back four with Toto Nsiala, Matthew Bates and Rob Jones all absent.
But Hignett refused to look for excuses.
It wasn't just the back four of Jordan Richards, Carl Magnay, Scott Harrison and Jake Carroll, who had off days - the entire team were not at the races.
"We missed players at the back but that’s no excuse," added the manager, who apologised to the travelling support.
"The fans deserve miles better than that.
"Every bit of stick I get and the players get is deserved. The performance was more than inept."