Oldham boss Lee Johnson admitted his side's 2-0 defeat to Preston was a "punch in the gut" as the Latics were dragged deeper into the mire at Deepdale.
Nicky Wroe notched his 11th goal of the season from the penalty spot in the 73rd minute after Oldham left-back Jonathan Grounds was adjudged to have handled in the area.
And with Latics goalkeeper Dean Bouzanis going up for a corner in injury time, Will Hayhurst rubbed salted into the wounds by tapping into an empty net.
Oldham did have chances with Jose Baxter going close on a number of occasions, but the Latics are now four games without a win and above the drop zone only on goal difference.
"We were comfortable and I was enjoying watching my team play as they were working very hard, but we get to that 60 or 65-minute point and crash," said 31-year-old Johnson.
"We did have some good chances, our set-piece delivery was excellent but you're just dying for someone to get on the end of it. I think right at this moment we just need that little bit of luck to get the break and that goal.
"I'm devastated as the boys stuck to the game plan perfectly and we worked our socks off. But this happens in football, sometimes it's like a punch in the gut.
"We find ourselves down there because we can only get to that 65, 70-minute period - then we die, and that's where most games are won or lost. The dressing room is obviously down, of course it is. I'm not going to sit here and say we're delighted - of course we aren't."
Preston moved up 15th, extending their unbeaten run at home to six, and boss Simon Grayson said: "It was a difficult game for us - we knew Oldham weren't going to lie down, they were going to battle and scrap because of where they are in the division and their result at the weekend.
"I thought they were better than us first half, they won a lot of second balls and a lot more individual battles. We knew we needed to up the tempo in the second half and we did. I felt if we stayed in the game long enough, Oldham couldn't sustain that sort of pressure."