Chris Wilder paid tribute to Newcastle United's 'really passionate fans' following Sheffield United's 2-0 defeat - but felt the game 'changed in a heartbeat' when the linesman raised his flag and Jonjo Shelvey's goal was awarded by VAR.
The visitors took the lead against the run of play following a fine header from Allan Saint-Maximin with a quarter of an hour played.
Sheffield United dominated possession and had a host of chances to equalise but found Martin Dubravka in inspired form between the sticks.
Newcastle doubled their advantage on 70 minutes when a long ball from Paul Dummett was flicked on by Andy Carroll, who was flagged offside by the linesman, into Shelvey's path.
While others stopped playing, Shelvey kept going and slotted home as the referee, Stuart Attwell, had not blown his whistle.The goal was subsequently awarded by VAR.
Wilder was keen to praise Newcastle's 'fantastic side who have got a wealth of talent in the team at the top of the pitch', but he spent much of his post-match press conference speaking about VAR and how it was 'sucking the life' out of him and Sheffield United supporters.
"I think if that was turned on its head tonight, at St James' Park, it would have been the same reaction. I think Sheffield United fans are mad but Geordies, they're absolutely off their nut them," he told reporters in his post-match press conference.
"Passionate, aren't they? Really passionate. You've seen them tonight when they've gone 2-0 up. Brilliant. Supporting the team, supporting Steve, so I'm not taking anything away from Steve's performance.
"I was a traditionalist at the start but it's every week. I don't think anyone knows where they are with anything, any decisions. There was a decision on Sunday when [Oli] McBurnie came in the last minute back stick and that wasn't even reviewed and other things get reviewed.
"The linesman sticks his flag up today and we were told at the start of the season that the linesman would keep his flag down. Yeah, I can criticise my players by not playing to the whistle but when everybody in the ground, even Jonjo, he didn't give me the impression he was in and he was 1v1 with Dean [Henderson].
"Then, five minutes later, the linesman puts his flag up and the referee blows. Scrutinising it is right because we have seen the clip but the game has just changed in a heartbeat. It's a difficult one to get your head around."