Leyton Orient manager Russell Slade felt his side were denied a "stonewall penalty" during their 1-0 home defeat to Colchester.
Saturday's League One clash at Brisbane Road was settled by Orient defender Terrell Forbes' own goal when he diverted Karl Duguid's low cross past his on goalkeeper Lee Butcher from four yards, while Kevin Lisbie appeared to be brought down by Magnus Okuonghae just before the break only for referee Mark Hayward to wave away appeals.
Slade said: "I always thought it was going to be one of those games that would be decided by a single goal and so it proved.
"But I'm convinced we should have had a penalty when Kevin Lisbie was brought down just before the interval. Their defender was all over him when he brought him down and in my book it was a stonewall penalty.
"Having said that, what concerns me is that we're not making the most of our possession when we're in control. We need to create more chances and show a clinical edge to our finishing when they do arrive.
"But full marks to Colchester. Visiting teams nowadays make it much harder for home sides to win. They come with a plan to stop you and Colchester succeeded in thwarting us."