England midfielder Ward-Prowse had only scored once this season, but he made it a birthday to remember with his superb set-pieces at Villa Park.
He is the ninth player in Premier League history to score two free-kicks in a single game and the first since Christian Eriksen for Tottenham in 2015.
Southampton move up to third in the Premier League after their fourth win in their last five games.
Ralph Hasenhuttl’s side lost their first two matches this term, but they have bounced back impressively and sit just three points behind leaders Liverpool.
On the heels of a 3-0 defeat against Leeds, Villa’s second successive loss served as a reality check after Dean Smith’s men won their first four league games.
Southampton made their pressure pay in the 20th minute when Jannik Vestergaard headed in Ward-Prowse’s free-kick.
Ward-Prowse curled a stunning free-kick past Villa keeper Emiliano Martinez from 25 yards in the 33rd minute.
His party celebrations were going with a swing and Ward-Prowse got his second when he whipped another majestic free-kick from the edge of he area on the stroke of half-time.
Danny Ings bagged Southampton’s fourth in the 58th minute, the England striker taking a touch from Stuart Armstrong’s pass before curling a superb shot into the top corner for his fifth club goal of the season.
Tyrone Mings reduced the deficit with a header from Jack Grealish’s cross in the 62nd minute.
There was a late blow for Southampton when Ings limped off injured.
Villa’s Ollie Watkins converted a 90th minute penalty after Ibrahima Diallo’s foul on Grealish, who scored third with the last kick.
Later on Sunday, second-placed Everton can knock Merseyside rivals Liverpool out of first place on goal difference if they win at Newcastle.
United and Arsenal, both languishing in mid-table after spluttering starts, can ill-afford to drop more points in their clash.
Arsenal have lost their last two league games, while United have failed to win any of their first three home league matches, including a 6-1 humiliation against Tottenham.
Tottenham host Brighton looking to climb into the top four in the final match on Sunday.
