Blackwell had much to think about after Thursday's Cup drama
Sheffield United boss Kevin Blackwell said referee Peter Walton apologised for his performance in the Blades' 2-1 FA Cup defeat at Hull on Thursday.
Walton gave Hull a goal when Blades defender Kyle Naughton's header was adjudged to have crossed his own line.
"The officials have to live with their mistakes but, to be fair to Peter, he rang and admitted he made major errors and that's big of him," said Blackwell.
"It is something that the referee hasn't had to do but he has."
Naughton's 24th-minute goal was controversially shown on the big screen inside the stadium, meaning the crowd were aware that the goal should not have stood, but referee Walton was unable to act.
Blackwell was furious with the decision after the game and called for goal-line technology to be introduced.
"I don't like seeing technology stop games, but that [decision] was instantaneous," said Blackwell.
"That's where I've been advocating goal-line technology is key.
"He knew he had made a mistake and had a chance to correct it before the game kicked off.
"But these idiots at Uefa who make rules put people in positions they can probably not backtrack from."
Controversial incidents cannot be shown on big screens under Premier League and Football League rules, but in FA competitions it is usually left to agreement between the clubs.
Hull boss Phil Brown admitted that controversially showing a replay of the incident inside the ground "could have started a riot".
Although United equalised through Billy Sharp, Hull went on to win thanks to a goal by Peter Halmosi, but Blackwell, 50, was also incensed after being denied a penalty after a tackle on Sharp.
Speaking before Walton's apology, Blackwell said: "We have lost a game we haven't lost. The official has made a decision and he is not 100% sure - that is what is the disgrace.
"I think (Walton) will look at that game and if we're being brutally honest, he won't be proud of that performance. If he was my player he'd be dropped."
The FA could investigate Blackwell's comments and a spokesman told BBC Sport that it would look into the situation and make a decision on Monday.
In March 2008, just a year after agreeing to developing the Hawk-Eye system, widely used in tennis and cricket, or a micro-chipped ball, the International FA Board - which makes the game's laws - turned its back on both systems.
It voted instead to experiment with two additional linesmen.
At the time of the decision, Uefa president Michel Platini said: "Either you help (the referee) with additional pairs of eyes or with technology, and I'm against technology. Once you start, who knows where you might stop. The 18-yard line, the offside trap?"