Both teams came into the clash at the AMEX Stadium on the back of Premier League defeats, with the Seagulls going down 1-0 to Everton, while the Villans were thrashed 6-1 by defending champions Manchester City.
For much of the first half, Brighton were the better side as they enjoyed the bulk of possession but they struggled to create any clear-cut chances against a Villa defence that looked fragile when put under any pressure.
However, the hosts broke the deadlock in the 39th minute when Neal Maupay fed a ball into the path of the onrushing Leandro Trossard, who fired a left-footed strike across goalkeeper Pepe Reina, who was making his debut, and into the bottom-right corner.
Villa’s best chance of the opening period came in first-half stoppage time when Anwar El Ghazi was presented with a free header in the box but his effort went wide with half the goal gaping.
The visitors must have received a stern word from manager Dean Smith at half-time as they came out with much better energy although chances were still at a premium for both sides.
Just when things were looking bleak, Villa got the crucial equaliser in the 75th minute when substitute Douglas Luiz played a beautiful ball to Grealish, who produced a sublime bit of control before rifling a half-volley into the top-left corner from inside the area.
It was a superb finish from the midfielder and, based on this performance, it would be no surprise to see him handed an England chance by Gareth Southgate in the next international break.
Brighton almost snatched all three points in the final minutes when Maupay fired a brilliant half-volley towards the bottom-left corner but shot-stopper Reina proved that age is just a number as he tipped the ball away.