Torres cost Liverpool around £20million last summer, and this goal - of all the 28 he has grabbed so far - could be the one that earns the riches that come from participating in Europe's premier competition each season.
Liverpool dominated the first half, and should have been in total command. Steven Gerrard hit a post and a hatful of chances were wasted.
But Everton, to their immense credit, tested Liverpool to the absolute limits in the second-half, and the Kop stood in anguish as they watched their heroes defend the goal in front of them.
But Liverpool hung on to complete only their 12th league double over the Goodison Park side in what was virtually a final eliminator for fourth spot.
Liverpool were missing the suspended Javier Mascherano, while Everton were without the injured Tim Cahill and Andrew Johnson - arguably damaging the Toffees' system more than the Argentina midfielder's absence for the Reds.
And after a spirited opening spell, in which Mikel Arteta tested Jose Reina with a spin and shot from 25-yards, Liverpool set about establishing a superiority on this 207th Mersey derby.
With so much at stake, financially as well as local pride, the game was tense and needed a firm control from referee Howard Webb, mindful of the 36 yellow and seven red cards in the seven derbies since Benitez took charge at Anfield.
In a fixture that has more dismissals than any other Premier League fixture Webb did a pretty decent job of keeping the passions in check.
He booked both Lee Carsley and Phil Neville - on his 100th league appearance for Everton - inside the first 18 minutes for fouls on Torres and Lucas, by which time Liverpool were deservedly in front.
And it had to be that man Torres.
The Spaniard may not have fared too well with goals for Atletico in the Madrid derby, just one, but he scored inside seven minutes of his Merseyside derby debut.
It was Liverpool's 100th in all competitions this season and he equalled the club record of scoring in six successive home league games, his 28th of a stunning first campaign in the Premier League.
It came when Xabi Alonso caught Ayegbeni Yakubu in possession 20 yards out, a situation the Nigerian should have had under control.
But he dithered and the ball was poked back into the box for Dirk Kuyt to flick forward. And Torres was on it in a flash, drilling the ball inside Tim Howard's far post with the normally solid Everton rearguard all over the place.
And for the next half-hour Liverpool pinned Everton back, searching for further success.
Kuyt had shots blocked by Tony Hibbert and Howard in quick succession, Ryan Babel missed a gift close-in from a John Arne Riise cross before a brave saving header from Carsley stopped Lucas reaching a Steven Gerrard free-kick.
Gerrard, himself, on his 20th derby appearance, then almost uprooted Howard's right-hand post with a fierce, dipping drive from 25-yards.
But the feeling remained that Everton were still in it despite Reina barely being tested.
Everton, with Arteta in a more central midfield role, and Steven Pienaar a wandering, sporadic influence, had unquenchable belief.
That was reinforced by the way they were over-powering Lucas in midfield, possession constantly being conceded.
And they started the second period with growing intent. Pienaar was booked for a foul on Babel as the Blues' tempo increased.
Neville's move to a more advanced role on the left of midfield forced Kuyt to defend and stopped Jamie Carragher getting forward. And Everton started to win free-kicks, their dangerous trademark.
Leon Osman sent a header just wide from one of Arteta's accurate deliveries, with Liverpool now having to defend. Manuel Fernandes came on for Pienaar on the hour, and Everton continued to press.
Phil Jagielka was booked for a late challenge on Gerrard before Neville was withdrawn - presumably injured because he headed straight down the tunnel after grabbing a track-suit top angrily, before exchanging a handshake with Moyes.
Liverpool gambled on sitting back and trying to catch Everton on the break the more they came forward, increasingly desperate to salvage something.
Babel was withdrawn to allow Yossi Benayoun into the argument, while Everton sent Jagielka up front late on. Everton were a constant and growing menace which needed all of Sami Hyypia's experience and Martin Skrtel's brawn to contain.
The unease in Liverpool ranks increased with Torres booked for time wasting, before being withdrawn, Jermaine Pennant coming on with two minutes left.
Kuyt curled a 20-yarder just wide and Howard saved superbly from Gerrard, but it was all Everton as the seconds ticked away.
Liverpool sent on Peter Crouch for Gerrard in injury-time as they successfully used up the last moments.