Andy Hessenthaler admitted his Gillingham players should be "ashamed" of their first-half performance in the thrilling 5-4 defeat to Bury.
Bury had led 2-0 at half-time courtesy of efforts from Andy Bishop and Ryan Lowe, before a remarkable second-half that included seven goals in 26 minutes.
Adebayo Akinfenwa pulled one back for the visitors two minutes after the restart, before Bishop regained the Shakers' two-goal advantage.
The Gills, however, levelled through Akinfenwa's second and Danny Spiller's drive, before Efe Sodje headed Bury back in front minutes later. Gillingham's Chris Palmer levelled with a sweet volley, although Lowe's second of the afternoon seven minutes later proved the decisive effort.
"It's a manager's nightmare - such a roller-coaster game," said Hessenthaler. "Since I've taken over the players have given everything, performances have been good, but they should be ashamed by the way they played first half.
"The positive is we reacted and had a go. We had to do something at half-time and we did, we went positive. But we've got to talk about ourselves. If you defend like that then you won't win any games. To come to Bury, score four goals and still come away losing is very disappointing."