Cardiff City manager Steve Morison questioned the decision not to award his side a penalty during their FA Cup fourth-round defeat at Liverpool.
When the game was still goalless, referee Andy Madley rejected Cardiff's appeal for a penalty after Mark Harris fell under Ibrahima Konate's challenge.
"If that's outside the box it's a free-kick so I don't know why that should change in the box," said Morison.
"We were performing pretty well and then we shouldn't be conceding from a set-piece [for the first goal]. Sloppy goals from us. We come away feeling frustrated with those moments but, on the whole, I think the players did themselves proud.