Chris Hughton criticised referee Stuart Attwell after Brighton were denied a "blatant" penalty during the 3-1 Premier League defeat to Burnley.
Albion boss Hughton was unhappy Attwell failed to spot an apparent handball by Clarets midfielder Jeff Hendrick.
Visitors Burnley broke away following the second-half incident and were awarded a spot-kick of their own moments later, which was converted by ex-Seagulls striker Ashley Barnes to make it 3-0.
A double from Chris Wood, another former Brighton player, put Sean Dyche's side in control at a rain-soaked Amex Stadium before Shane Duffy pulled one back with a consolation.
Video Assistant Referee technology is not currently used in the top flight but Hughton felt the match officials should not have required assistance to award a penalty.
"We needed a momentum and probably the disappointment – at 2-0 – we have what is a blatant penalty which is not given," said Hughton.
"And they go up the other end and score. Probably, that was our day today. The moments we needed to show quality we perhaps didn't.
"(It was) a decision that shouldn't need VAR. We have a referee that's probably 10 yards away and a linesman that's supposed to help him out in those situations if he hasn't seen it.
"It wasn't, for me, a difficult one to see. VAR or no VAR, it's one that a referee should have seen.
"If we were to have that penalty, which we should have done, we score it, it's 2-1, we're back in the game, momentum shifts in our favour."
The result, which extended Albion's winless run to six top-flight games, drags Hughton's side back into relegation danger.
The 14th-placed Seagulls sit level on 27 points with Burnley, three points above the bottom three.
"We probably don't want to speak that way (about a relegation battle) but we are a level of club that's going to have ups and downs and everything's not going to be smooth for us," he said.
"When anybody felt that we might have been in a comfortable position in the league, we never ever felt that.
"We know how difficult this league is and the quality of the teams below us that can all win games.
"This is a time really to make sure we are aware of that and we need to get points."
Victory for Burnley secured a club record seventh successive Premier League game without defeat.
The Clarets, who slipped into the relegation zone ahead of kick-off following Cardiff's dramatic win at Southampton, have now taken 15 points from a possible 21 since a 5-1 Boxing Day thrashing at home to Everton.
Manager Dyche says he could "smell" mental strength returning to his players after a difficult start to the campaign following last season's unexpected Europa League qualification.
"Pleased with seven unbeaten in the Premier League, it's another historical marker for these players," said Dyche.
"Mostly pleased for the mentality of the group because heavy questions this year, different kind of season. Still more to come but lots of questions, lots of confusion, lots of odd things, lots of differences, lots of new challenges and culminating in a tough day on Boxing Day when we had to realign. They (the players) take massive credit for that.
"It just floods back in very quickly, no-one can put their finger on it.
"When it goes you can smell it coming back again, it's a strange thing. After West Ham (a 2-0 win on December 30) you could feel it coming back again into the group."