Phillips, forced to leave the Black Cats along with the other big wage earners after their relegation from the Premiership three seasons ago, set Villa on their way to a comfortable victory.
Further goals from the impressive Gareth Barry and Milan Baros condemned Sunderland to a fifth successive Premiership defeat and left the home fans facing another long winter of discontent.
Just as the Black Cats collapsed in the second half against Portsmouth in their last home match, they had nothing in the tank to respond to Villa making the crucial breakthrough after 55 minutes.
Yet the hosts started strongly and Jon Stead, Tommy Miller and Alan Stubbs all threatened Thomas Sorensen's goal in the early stages.
But Phillips, given a resounding reception before the kick-off, showed just what the home fans have been missing since his departure. The former Golden Boot winner cut in from the left and only a diving save from teenage goalkeeper Ben Alnwick kept the sides level.
Villa, however, should have gone ahead in the 18th minute. A deep centre from James Milner was headed back into the middle by Baros, only for Barry to completely mis-hit his close-range effort and allow a grateful Alnwick to save.
Sunderland though had a great chance early in the second half. Nyron Nosworthy broke down the right and fed Stead, whose low cross was hammered over the bar by Anthony Le Tallec.
Predictably it was Phillips who forced the breakthrough ten minutes after the break. A clever back heel by Baros gave Aaron Hughes the chance to cross from the byline for Phillips to head past Alnwick.
Sunderland's response deserved better luck, for within a minute the tireless Christian Bassila crashed a thundering drive against the underside of the bar with Sorensen well beaten.
Phillips limped off after 68 minutes to be replaced by Luke Moore, who should have put the issue beyond doubt three minutes later when sent clear, but allowed Alnwick to smother his close-range effort.
The miss proved academic as Barry was on hand to apply the finishing touch at the far post to a Milner cross in the 81st minute, and within 60 seconds Baros went clear from a clever flick from Moore to leave Alnwick helpless.
A trip by Liam Ridgewell on Stead in the last minute gave Dean Whitehead the chance to score a consolation from the penalty spot, but it was much too late to give the home fans any hope.
Man of the match: Gareth Barry.
His tireless running from midfield was finally rewarded with the goal that killed off any hopes of a Sunderland fightback. On another day he could have had a hat-trick.