Paul Dickov felt a lacklustre first-half showing was at the root of Oldham's 2-1 derby defeat to Bury at Boundary Park.
The Shakers dominated the first half and deserved their 34th-minute breakthrough when Matt Doherty crossed from the right and Cliff Byrne's defensive header hit Oldham team-mate James Tarkowski before going in for an own goal.
Oldham responded after the break but Robbie Simpson, Jonathan Grounds and Jose Baxter were unable to convert chances. Bury duly doubled their lead in the 86th minutes, Steven Schumacher slamming in a penalty after Tarkowski brought down David Worrall, before Simpson's deflected header set up a grandstand finish.
"We were really poor in the first half and it was Bury who showed more energy," said Latics boss Dickov. "We have been doing ever so well recently, but we looked a different side compared to the last few weeks.
"Bury were better than us in the first half and you can't afford to start games in the way we did. Usually it's us getting three or four men around the ball when the opposition have possession, but it was the other way around.
"Everyone is striving for consistency, but we were too lethargic with and without the ball. It makes me feel sick that we've lost the game and it's very frustrating that we let our standards drop."