The Spaniard headed home in the 89th minute after Chelsea had been reduced to 10 men by a red card for midfielder Frank Lampard and then made sure of a league double over the Londoners with a second in stoppage time.
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It was a bitter blow to Chelsea's title hopes although they could have few complaints as they barely mustered a shot on target even before Lampard was harshly sent off by referee Mike Reily for a tackle on Liverpool midfielder Xabi Alonso.
"After the Lampard sending off they had more possession, more quality, more chances in front of goal, but until then, no," Chelsea manager Luiz Felipe Scolari told Sky Sports.
"I want the referee to look at that decision on TV and change his decision. It was a foul by the other player not Lampard."
Liverpool, who had drawn their previous three Premier League matches, moved back above Chelsea into second place with 51 points from 24 games, two points behind champions Manchester United who have played a game fewer.
At the other end of the table Newcastle United and Sunderland drew 1-1 in the north east derby to leave both clubs in the thick of the relegation dogfight.
Liverpool manager Rafael Benitez had come under increasing scrutiny since his outburst at United manager Alex Ferguson last month and their rival's surge to the top of the table.
His decision to axe striker Robbie Keane from the squad looked baffling during a tepid first half, but Torres burst into life to spare him further inquests.
"He showed that he can score important goals and it's great to see him back so hopefully he can score more between now and the end of the season," Benitez said of Torres before adding that Keane was not leaving the club.
Torres, who has missed important chunks of the season with injuries, had been largely anonymous for most of the match as Liverpool toiled to break down the visitors.
He had not scored a league goal since October but chose the perfect moment to show what a lethal striker he is.
Cech had saved well from Alonso and substitute Yossi Benayoun after the break as Liverpool drove forward but he was powerless when Torres glided into space at the near post to head Fabio Aurelio's cross into the net.
There was a huge sense of relief among Liverpool fans, who have seen their side's attempts to win a first league title since 1990 stall in recent weeks, and they were celebrating wildly deep in stoppage time when Torres struck again after Benayoun robbed Ashley Cole.
Chelsea's only shot on target came from Salomon Kalou 16 minutes from time and they trudged off at the final whistle with their title hopes fading rapidly.
"We were not good today, they were better for all the game," Scolari conceded. "We need to look again, and try again because we have many games and we need to fight until the last game."
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