Benitez's side escaped an early chance with Zavon Hines hitting the post but Torres burst into the box to power in the opener past keeper Robert Green.
Dirk Kuyt regained their lead, only to see Carlton Cole shock the visitors with a headed equaliser on the stroke of half-time, before Torres popped up to grab the fifth and all-important goal.
Earlier in the week Torres had revealed that he was playing at less than 100%, while Benitez had said the Liverpool striker was "not at his best".
Hard work pleases Torres
But Torres' double at West Ham means the Spanish international has scored five league goals this season and Benitez added: "He is a very good player and it is easy to see his qualities. If he is keen to learn, he will improve.
"He is now fit and we are working hard with him to prevent injuries. Hopefully he won't be injured and he can score a lot of goals for us but we have different options.
"We were in control of the game [against West Ham] and the reaction of the team was very positive."
West Ham boss Gianfranco Zola also described Torres as a "great striker" but saved most of his compliments for his own team who overcame the loss of injured Matthew Upson and Valon Behrami in the first half.
"It was very encouraging," said Zola, celebrating a year in charge at Upton Park. "We were unfortunate not to pick up any points. But we will get better and it won't be long."
The Italian boss was understandably delighted with Hines after the 20-year-old Jamaican-born winger struck the woodwork after two minutes and won their penalty after being bundled over by Jamie Carragher.
Hines wins the penalty and was a handful throughout for the Reds
"Zavon has done very well in the last week but he was even better against a difficult team," said Zola about the player making his second Premier League start.
"The boy is taking his chances very well. He helped the team defensively and he is establishing himself, which is down to his work and attitude.
"You need to have players like him. I am hoping a few others will do the same in the next few weeks. He is playing with a brave attitude and making an impact."
On Alessandro Diamanti's controversial spot-kick that saw the forward slip over and appear to hit the ball twice, Zola said: "His penalty was very scary.
"I think he slid as he took it, but he said that he meant to do it. But he had a good game and worked a lot for the team."
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