Clayton Donaldson scored twice as the Blades hit back from two early set-backs to earn a pre-Christmas point.
Villa took a 2-0 lead inside 10 minutes but thanks to Donaldson the Blades were level inside half hour in an entertaining fixture.
Blades Wilder made two changes with Duffy and Donaldson returning to the starting XI, in the places of Carruthers and Sharp, who dropped to the bench.
Little more than three minutes had elapsed when the first serious foray into either box resulted in a penalty. Stearman was adjudged to have caught Davis and referee Hooper pointed to the spot, from which ADOMAH beat Moore.
On nine minutes Villa doubled their lead, the result of another set-piece. Snodgrass delivered a free-kick and JEDINAK rose highest to head home in a crowded box.
Blades fans were reeling from the start but with the next attack, the visitors hit back. Lundstram's ball over the top of the defence was superbly controlled by DONALDSON, who then lofted a chip over goalkeeper Johnstone.
It was the signal for the Blades to get on top, Baldock had an effort blocked before the scores were levelled on 26 minutes. Jedinak failed to cut out Duffy's pass and DONALDSON took advantage, blasting under Johnstone.
After a hectic opening half hour, the frenetic action continued up until half-time. From a deep Elmohamady cross, Adomah beat Baldock in the air but headed wide and at the other end Donaldson was crowded out at the back post, whilst from the resulting corner, Johnstone clawed away from Carter-Vickers.
Before the interval Hourihane's effort deflected off his own player and Snodgrass fired a free-kick into the wall.
There was a more sedate start to the second period, although Moore was forced to save after Snodgrass cut in from the right.
On 50 minutes Lundstram won possession, allowing Clarke to set up Duffy but his shot was pushed over the crossbar by Johnstone, whilst just after the hour skipper Clarke headed wide a Duffy cross to the back post.
Basham, already on a booking, had a nervous chat with the referee after pulling back Grealish, whilst Moore was well-placed to keep out Chester's header from Hourihane's free-kick.
Carruthers and Sharp were introduced and late on the chances dried up, both sides keen not to present opportunities. Lundstram worked particularly hard to keep Villa at bay and as the game entered four minutes of injury-time Clarke headed wide a Stevens cross.
The added time failed to produce a further chance, the draw taking United to 38 points at the halfway point of the season.
Villa: Johnstone, Taylor, Chester, Whelan, Snodgrass (De Laet 58), Grealish, Hourihane, Jedinak, Elmohamady (Hogan 73), Adomah, Davis (Agbonlahor 73).
Unused: Steer, Bjarnason, Hutton, Elphick.
Blades: Moore, Baldock, Stevens, O'Connell, Basham, Lundstram, Clarke, Donaldson (Sharp 73), Carter-Vickers, Stearman, Duffy (Carruthers 73).
Unused: Wright, Lavery, Heneghan, Lafferty, Blackman.