A flat game was heading for a goalless draw until ragged Villa defending allowed the ball to slip into Torres's path and he calmly placed a low shot beyond Brad Friedel.
The Spaniard's predatory finish was his 50th league goal in 72 matches - the quickest a Liverpool player has reached that tally - and was the only memorable moment from a poor game.
Villa, having beaten Liverpool, Chelsea and Manchester United this season, were denied a big four clean sweep by Sunday's 3-0 loss at Arsenal and that perhaps had a chastening effect as they were cautious from the start on Tuesday.
TERRIFIC REFLEXES
"Everyone knows when he's on form he's the best in the world, we want him to score many more goals like that and drive us into the top four," Liverpool captain Gerrard told Sky Sports.
"We're hoping this gives us a big boost. Villa, Spurs and Man City are going to keep fighting all the way and we need to do the same.
"It's important to build on this. We've virtually got everyone back fit now so there are no excuses. We need to go on a run of winning games."
Villa manager Martin O'Neill said: "We should have won but not only did we not, we lost. "We had the chances, it's a blow to the team but we will fight back."
In Tuesday's other game, Hull City fought back from two goals down at Bolton Wanderers to force a 2-2 draw thanks to a Stephen Hunt double but both teams remain in the drop zone.
