Walsall manager Dean Smith was left counting the cost of early and late drama after the Saddlers went down 2-1 at Oldham.
The struggling League One club fell behind to Filipe Morais' goal after just 73 seconds and also wasted a golden opportunity to snatch an injury-time point when Oldham goalkeeper Alex Cisak saved an Alex Nicholls penalty.
In between, Robbie Simpson extended the Latics' lead before Florent Cuvelier pulled a goal back for Smith's side.
"There wasn't much in the game in the first half and both Oldham goals were down to our bad defending," said the Saddlers boss. "You always want to make a good start but one of our players mis-kicked, we didn't defend the situation well and we found ourselves behind straight away.
"Then we should have done much better for the second, so we were 2-0 down without Oldham really having to do anything. We keep making mistakes but we got ourselves back into it in the second half and obviously had the penalty right at the end.
"Penalties are scored and missed at every level whether it's the European Championships or League One, so you don't blame anyone when you don't score. But it's very frustrating that the penalty didn't go in and it's annoying that we don't understand what's required defensively."