Boss Joe Royle felt his side ought to have had a first half penalty when Darren Bent was clearly felled inside the area and said he was surprised at the appointment of relatively inexperienced officials for a fixture which could have determined both a promotion and a relegation.
The Town manager said: "The officials were not up to a game of this stature. But it doesn't matter - because we didn't win the game.
"But we have to pick ourselves up. We play West Ham in the play-off semi-final, and we will focus on that.
"I am not worried about the fact that they beat us at this stage last year. We finished 12 points ahead of them in the table.
"We have been defeated only once in 10 matches, so we go into the play-offs in decent form."
Brighton boss Mark McGhee had particular praise for his side's scorer: "It was a Lazarus performance from Adam Virgo. He rated himself only 40% fit on Friday.
"But he then asked if could have an injection and, after we had made sure it would be no risk, he was given it and was able to play.
"He is becoming a bit of a legend here. He has played in a number of positions this season, has done everything that has been asked of him and has been outstanding. Let's not forget he is also our top scorer with nine goals."
McGhee admitted to a few nerves in the closing stages, a Town goal meaning his side would be in League One next season: "The last 20 minutes were scary. We were sitting back and they were pouring forward.
"So it was pretty frightening. These kinds of relegation battles are not something I have experienced before - and it's not something I want to do every year.
"The last two games have been very, very draining, but you have to put yourself into a bubble. The key is to concentrate only on the game and not on the possible consequences."