Villa suffered a second straight defeat in the Barclays U18 Premier League despite an encouraging fightback against Southampton.
Callum Robinson and Liam Bateman were on target for Tony McAndrew's team but it wasn't enough to earn them a share of the spoils at Bodymoor Heath.
The Saints took the lead on 12 minutes when Ryan Seager swept home a rebound after Dominic Gape's initial effort was blocked.
The lead was doubled in the 19th minute when Jake Flannigan converted Gboly Ariyibi's cross.
But Villa responded well after the break and Robinson pounced in the penalty area on 56 minutes to pull a goal back.
It was soon followed by an equaliser, which arrived when Bateman's shot went in with the aid of a deflection from a Southampton player.
However, the Saints had the final say with Omar Row burying a late effort to ensure they returned to the south coast with all three points.