Jordan Lyden's equaliser earned a deserved share of the spoils for Villa in a well contested match at Crawley Town's Checkatrade.com Stadium.
Lyden captained the visitors, dressed in their yellow and black away kit and they were on top in the opening stages.
The B6 lions carved the first chance of note on 11 minutes when Andre Green let fly with a rasping drive from distance which Christian Walton clawed behind.
The all-action Lyden's header was on target from the resultant corner but saved.
With Villa in the ascendency, Henry Cowans hit one of his trademark free-kicks which drifted just wide of the post.
Jonah Ayunga was a threat down the Brighton left and he did well to work his way past Josh Webb but shot into the side netting.
Ever a driving force in midfield, Lyden demonstrated a good burst of pace, played a clever one-two with Green but the claret and blues' skipper was beaten to the ball by Walton.
The home side finished the first period strongly.
With five minutes remaining, the Seagulls carved their best opportunities and put Kevin MacDonald's side under the cosh.
Chike Kandi's strike was blocked by goalkeeper Matija Sarkic before James Tilley's tame effort was into the arms of the goalkeeper.
The message from both managers at the interval was clear - attack and try and draw first blood early doors.
Brighton almost obliged on 48 minutes - Jesse Starkey's stunning strike from 35 yards cannoned off the crossbar with Sarkic rooted to the spot.
At the other end, Green embarked on another impressive run down the left flank, put in a couple of crosses met by Sellars, who volleyed over the bar.
The Sussex side took the lead through an emphatic strike from defender Ben White - volleying home from a corner after a sustained spell of pressure.
Much like in many of their Barclays U21 Premier League Division Two matches this season, Villa showed spirit, belief and determination to work their way back into the contest.
They surged forward and a clinical strike from Lyden, with two of his team-mates also lurking in the area, finished off a lightning-quick move and levelled the scores to cue jubilant celebrations.
In the relatively even closing stages, the Seagulls worked their way into some good positions but lacked a killer instinct, perhaps unsurprising given their league position.
Tilley embarked on a run but could not direct his strike on target.
Winger Green was a constant menace down the flank and his ball found Sellars, whose shot was scrambled behind for a corner as the visitors searched for a winner.
Australian Lyden almost grabbed the points for his side in second half stoppage time - meeting substitute Jake Hayes' corner, his header well saved by Walton.
It was end to end as the match drew to a close.
Substitute Ragnar Mar Larusson had a double chance - his first strike is saved by Sarkic and the follow-up was wide.
With virtually the last kick of the clash, Rory Hale came close to capping off a crisp attacking move, his low strike was gathered by the Brighton stopper.
Brighton U21: Walton, Hunt (C), White, Hutchinson (Collar 69), Barnett, Molumby, Starkey (Harper 88), Tilley, Kandi, Bjordal, Ayunga (Larusson 65). Unused subs: Ward, Lynch Sanchez.
Villa U21: Sarkic, Webb, Suliman, Mason, Swift, Hale, Lyden (C), Cowans (Hayes 73), Abdo, Green, Sellars (Mooney 86). Unused subs: Johannson, Clark.