Tranmere boss Les Parry conceded Oldham were the better side after they won 2-1 at Prenton Park.
Latics midfielder Dale Stephens, 20, struck in the 27th minute with a fine free-kick which sailed into the bottom corner from 18 yards.
Stephens added a killer second with another fine finish with nine minutes remaining to ensure Ian Thomas-Moore`s late strike was no more than consolation.
Parry said: "We've had a lot of injuries which have been disruptive but it is no good making excuses.
"Naturally we are very disappointed. We did not get at Oldham soon enough. I don't think either side really deserved to win the game which wasn't one for the purists. They took their chances. We did not. It is as simple as that.
"We had a free header to take the lead in the first half but missed it. We needed to make their keeper work harder and we didn't. We should have got more crosses into the box. It was nice to get a goal but it came too late to really give us a chance."