The Reds remain in the bottom half of the table but they at least gave the Anfield faithful something to cheer after they had been forced to endure a miserable start to the campaign.
They appeared to have hit a new low in the midweek Carling Cup defeat at Crystal Palace but responded in the right manner against Alan Pardew's side.
Xabi Alonso's long-range effort gave Liverpool a half-time lead and substitute Bolo Zenden sealed all three points with his first goal for the club in the closing stages.
Benitez opted for a 4-4-2 formation with John Arne Riise returning to left-back among seven changes from the side that lost at Selhurst Park. Peter Crouch was left on the bench as Fernando Morientes started in attack.
The Hammers had Anton Ferdinand and Yossi Benayoun back after minor injuries while loanee David Bellion made his full Premiership debut for the club.
The visitors started brightly and Paul Konchesky's free-kick caused danger in the Liverpool defence before Marlon Harewood inexplicably turned the ball away from goal.
When Liverpool hit back Steven Gerrard's cross forced a corner that resulted in Luis Garcia cutting in from the right to fire in an angled shot which Danny Gabbidon blocked.
But in the 18th minute Garcia's corner was only partially cleared and Alonso sent in a low drive which flicked off Tomas Repka's head and curled past Shaka Hislop in the Hammers goal.
Gerrard then went close to adding a second two minutes later with a fierce 20-yard drive that flew just wide.
Sami Hyypia had a header blocked on the line by Konchesky, who then kept Morientes' effort out as the Spaniard latched on to the rebound.
Repka's cross almost caught Jose Reina off his line but Liverpool remained on top with Gerrard wasting a good opportunity by being too unselfish.
Morientes should have made it 2-0 when he met a Gerrard cross but could not direct it far enough away from Hislop's dive.
The veteran keeper then produced the save of the match to turn away Garcia's shot after Gabbidon had been caught in possession.
Zenden replaced Djibril Cisse, and with his first touch the Dutchman produced a cross which Garcia headed wide of the far post.
But the second goal eventually came with eight minutes left when Riise's headed clearance dropped into Zenden's path and the former Middlesbrough midfielder cut into the penalty area before drilling a shot in off the far post for his first goal for the club.
MAN OF THE MATCH: Xabi Alonso (Liverpool) – Scored the all-important opening goal that settled the home side's nerves but the Spaniard was a driving force in the Reds midfield throughout as he kept the hosts ticking over.