Keith Downing had no argument wth the penalty decision which sent his side out of the FA Cup at Withdean.
But the Cheltenham boss was not happy with the incident which saw Shane Duff head off the underside of the bar as Albion clung to their 2-1 lead.
Downing did not know whether the ball had crossed the line and agreed Paul Connor was offside when he deflected it home later in the melee.
But he said: "I was more disappointed we didn't finish it as it came off the bar. There were a lot of bodies there to put the rebound in.
"One or two of the players thought it might have gone over the line.
"That's the way it's going at the moment but I'm not going to give a hard luck story."
Downing put the spot kick, conceded by Gavin Caines for impeding Nicky Forster, down to a collective failing.
He said: "It was avoidable. Shane Duff went under the ball, Gavin hasn't dealt with it.
"The manner and the timing of it really kills you.
"I thought it was a penalty. The only debate then is does he stay on or go off.
"I thought there were times when we got Brighton not on the back foot but when they were just running out of ideas.
"It doesn't help when you claw your way back into the game, then you give away a goal like that."
Downing revealed Steven Gillespie, Cheltenham's most dangerous attacker, was taken off through fatigue rather than injury after a tough week.
Did you think it was a penalty? And was that ball over the Albion line? Leave your comments below
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