Youth Team boss Tony Philliskirk felt his side lacked the sufficient physicality as Latics' youth team were dumped out of the Lancashire FA Professional Youth Cup by neighbours Rochdale.
Three second half goals from Rochdale sealed victory through to the semi final of the competition in which Latics youth team, who are sponsored by the Safeguard Group, won last season after beating Blackpool on penalties.
Philliskirk said: "We tired in the second half but I'm not making any excuses because we have to defend better. We looked weak in the second half defensively.
"They were a lot more physical than us and the back four didn't cope. If they want to make it in the game, then you have to rise to the physical challenge.
"In the first half, we were happy to pass the ball around and make it look excellent but Rochdale changed their game and we couldn't match them.
"I thought the first half was the best we played in a long time, though. We had some of our second year players back in the side and it was great to see them back.
"We should have been three or four nil up in the first half as we were assisted with the wind but second half the wind affected us and Rochdale pressed us well.
"Rochdale's first two goals were individual errors from ourselves and at the end we were chasing the game so we conceded the third.
"I was disappointed to go out of the cup but I saw a lot of promising signs in certainly the first half as it is the best football we have played in a while but we are just lacking a bit of a ruthless streak.
"As soon as they scored, you could see our heads drop and then they were in the ascendancy. In the end, it was the ultimate game of two halves."
Controversy surrounded Rochdale's second goal which put them in the lead and the manager felt the decision changed the game.
"The lads are adamant it didn't go over the line. A couple of their lads said it was, others weren't sure but the linesman gave the goal," admitted Philliskirk.
"We have tried to watch it back on the DVD but you cannot really tell whilst George Edmondson, who cleared it off the line, said that it definitely didn't go over the line.
"That decision changed the game and put them 2-1 ahead and that made us change our system to try and get a goal.
"They ended up exposing us and went on to win 3-1 but I wouldn't have been forced into that change had the linesman not given the goal and it could have been a different game."
The gaffer welcomed back former Wales under 17 winger Danny Byrnes back into the squad after his long injury lay off and he admitted it is a big lift to get him back in the squad.
"It was his first game of the season and it looked like he had never been away. He started to cramp up towards the end of the game but we tried to get as many minutes as we could out of him but he performed really well.
"He will add that extra bit of quality back into our side because he's very positive going forward and once we get him back to speed we will be even more of a threat," said Philliskirk.