The 20-year-old striker got Atletico off to a flying start at the Nou Camp when he guided home in the first minute after a stunning back-heeled assist from playmaker Ariel Ibagaza.
World Player of the Year Ronaldinho fluffed a 70th-minute penalty for Barcelona before Torres completed a shock victory when he blasted home a spot kick deep into injury time.
Atletico's victory meant that Real Madrid, who beat Espanyol 4-0 on Saturday, are four points behind Barcelona in the standings with the two sides yet to meet at the Bernabeu.
The race for the title has effectively become a two-horse affair with Real nine points clear of champions Valencia, who were held to a 3-3 draw by struggling Real Sociedad on Saturday.
Earlier Seville moved into fourth after a 3-0 win over Levante with striker Julio Baptista's superbly struck 25-metre free kick five minutes from time the goal of the match.
Villarreal climbed into fifth, one point further behind, with their fifth win in a row after they came from a goal down to beat 10-man Racing Santander 2-1 at home.
Striker Diego Forlan scored his 14th of the season when he slid in at the far post early in the second half and playmaker Juan Roman Riquelme snatched the winner from the penalty spot.
EXPLOSIVE START
Atletico, who had won only one previous match away from home all season, got off to an explosive start thanks to some great skill from Ibagaza.
With his back to goal the Argentine midfielder hooked a pass over the defence with his heel to give Torres a free run on goal and the striker outpaced defender Carles Puyol before threading the ball past Valdes inside the far post.
Barca threw players forward in search of an equaliser, but were thwarted by the watertight Atletico defence and they grew increasingly frustrated as their constant stream of attacks failed to pay off and Samuel Eto'o and the lively Ronaldinho were reduced to trying their luck with long-range efforts.
Atletico almost snatched another goal at the end of the half after the ball fell to Torres inside the area, but Valdes made a fingertip save to turn the shot around the post for a corner.
Barca pinned Atletico back in their own area for most of the second half, but rarely troubled keeper Leo Franco and only had a chance to equalise when they were wrongly awarded a penalty when Perea clipped the heel of Eto'o outside the area.
Ronaldinho slammed his spot kick wide of the post, but Torres made no mistake with his when he was felled by Valdes as he raced into the area three minutes into stoppage time.
