Without their skipper, it is questionable whether Villa would have avoided a second round embarrassment for the second time in three seasons against the League One Brewers.
Dean Smith’s team trailed after just 64 seconds of their first competitive match of the 2020/21 campaign to Colin Daniel’s opener and were struggling to get on level terms, before a brilliant piece of skill from Grealish helped set up Ollie Watkins’ first goal for the club.
Then, with just two minutes remaining and a penalty shoot-out looming, Grealish finally broke Burton’s brave resistance when he volleyed home Henri Lansbury’s corner.
Substitute Keinan Davis then added a third in stoppage time, Lansbury again the supplier, to set up a third round trip to either Bristol City or Northampton Town next week.
Grealish was one of three players, along with Tyrone Mings and Watkins, from what would now be constituted Villa’s best XI to be named in the starting line-up.
Smith also handed a full senior debut to midfielder Jacob Ramsey, while Lansbury made a rare start.
Burton had played three competitive matches prior to this and caught Villa cold.
The instigator of their opening goal was wideman Ryan Edwards, who was quick to charge down an attempted Neil Taylor clearance. Seconds later the ball was back at his feet allowing him to deliver a low cross which Daniel arriving unmarked at the far post, rifled into the roof of the net.
Villa looked to find a quick response but found Burton’s defence sturdy. Kortney Hause headed a Grealish cross over the bar, while Ramsey was unable to make a clean contact on an inviting Anwar El Ghazi pull-back.
In the end it took a moment of magic from Grealish to help his team back on level terms six minutes before the break.
Picking the ball up on the left, the Villa skipper turned this way and that, drawing the attention of three defenders before flicking a deft pass through to Neil Taylor.
The pass was so well disguised, it momentarily fooled his team-mate, who after locating the ball delivered a low cross for Watkins to tap home at the far post.
Having got level, Villa almost found themselves behind again when Marvelous Nakamba lost possession cheaply in midfield and Edwards curled a shot wide from the edge of the box.
Yet Watkins was then guilty of missing a great chance to get his second and put the visitors ahead. Grealish again was the creator, collecting the ball by the corner flag and embarking on a run in line with the touchline before pulling the ball back to Watkins, who could only turn his shot against the bar.
The first big chance of the second half fell to the hosts. Mings misjudged a header, allowing Kane Hemmings to steal in and fire a shot wide of the post.
Grealish continued to be at the centre of Villa’s best work, at one point attempting an audacious volley from wide on the right wing which momentarily had Burton keeper Teddy Sharman-Lowe scrambling.
The hosts were right in the game though and Lukas Akins went close when he saw a shot blocked after bursting through the middle.
At the other end, Burton skipper John Brayford almost deflected an Elmohamady cross into his own net.
Smith brought on Jota with 10 minutes remaining and the Spaniard almost won it for Villa with a shot which whistled just over the bar.
In the end the honour went to Grealish. His connection with Lansbury’s corner was not the cleanest but was directed toward the corner and with enough power to beat Sharman-Lowe.
Burton (4-4-2): Sharman-Lowe, Fox, Bostwick (Gallacher 25), Brayford, Daniel, Edwards (Powell 66), Quinn, Wallace, Lawless (Gilligan 66), Akins, Hemmings Subs not used: Anderson, Hewlett, Williams, Garratt (gk).
Villa (4-3-3): Nyland, Elmohamady, Hause, Mings, Taylor, Lansbury, Nakamba, Ramsey (Luiz 71), El Ghazi (Jota 80), Watkins (Davis 71), Grealish Subs not used: Guilbert, Konsa, Samatta, Steer (gk).