Gillingham manager Justin Edinburgh has described his side's performance in their FA Cup defeat at Stevenage as "totally and utterly unacceptable".
The Gills, who are third in League One, lost 3-0 at League Two side Boro.
"Apologies to the supporters who travelled in numbers - it was a big black mark against our name," the 45-year-old told BBC Radio Kent.
"People are going to lose their places in the team off the strength of that. It won't be allowed."
Stevenage went into the first round tie 42 places below Gillingham in the Football League, and with just one win in their previous 10 league games.
However, the Gills were 2-0 down inside half an hour through goals from Steven Schumacher and Chris Whelpdale, and on-loan striker Armand Gnanduillet completed the win for Stevenage in stoppage time.
"We were outplayed and outworked. It is not what we are about," Edinburgh said.
"There is not a player that comes out with any credibility. I would never have expected or envisaged that performance. It hurts."
|No Cup of cheer for Gills|
|Gillingham have lost in the first round of the FA Cup in the last three seasons|
|Two of those defeats have come against lower-league opposition - Brackley Town in 2013-14 and Stevenage this season|
Edinburgh now plans to make changes to his side for Tuesday's Football League Trophy tie at home to Yeovil.
"It is something which can't happen again," he said.
"Reputations after 16 games of the season don't warrant anything. We have got to get back to the drawing board and back to what we do well.
"I am as accountable as anyone; that is my team, it was my selection and my players. I will stand with them and take the responsibility."