Crawley manager Richie Barker felt a draw would have been a fair result after his side's 2-0 home defeat to Sheffield United on Saturday.
Barker felt referee Gavin Ward got his decision wrong when awarding the free-kick that led to Blades defender Tony McMahon's 29th-minute opener at the Broadfield Stadium.
McMahon fired home an identical free-kick in the second half to lift the Blades above Tranmere into top spot in League One, but Barker felt his side were hard done by.
Barker said: "I must be careful what I say, but it wasn't a free-kick. I'll make sure the feelings are felt. If it is a guess it has cost us.
"We didn't get the rub of the green with the referee's decisions. It changed the game and it allowed them to get a foothold.
"We kept plugging away very well, but it was never going to be easy against a side of their quality, especially in such difficult conditions."
Barker remains satisfied with his side's haul of 35 points and has challenged them to double the tally in the second half of the season.
He added: "The players should take immense pride from that performance against a side who will probably win the league.
"Should we get another 35 points now we won't be a million miles away from the play-offs come the end of the season. All things considered, the players have been fantastic.
"I only came into the job six days before the start of the season and in the next month I'll try to shape the squad the way I want it."