After an opening twenty minutes in which Rovers were pushed back for the majority, Scott Dann stunned the home fans by heading the opening goal.
But the turning point of the game came minutes into the second half when Jordan Rhodes' shot struck the arm of El-Abd, but no penalty decision was forthcoming.
To add insult to injury Markus Olsson was then penalised for a handball of his own moments later, Vincente making no mistake from the spot to level the scores.
Albion pressed for a winner but Rovers held firm to claim a hard-fought point on their travels.
"It could and probably should have been a lot different," said Appleton after the game.
"Lets face it, the best save of the night has been by one of their central defenders.
"If the penalty is given it's 2-0 and the game is totally different.
"Then to say the one given against us was a harsh one was the biggest understatement for a while."
Appleton was delighted with the way the side coped with the relentless pressure put upon them at times, the team having to defend manfully for long periods.
"It was a noisy atmosphere and a good atmosphere for them to play in. The way we stood up to it at times and dealt with it, the players deserve all the credit they get.
"Brighton are where they are for a reason, they are a good side and we stood up for it, there was a good shape about us.
"We could have easily thrown the towel in once it went to 1-1 and caved in under the pressure, but we didn't we stood firm, I was delighted with that, they defended attack after attack really well."