A trophyless campaign for Jose Mourinho ended on something of a high as Chelsea scored twice in four second-half minutes following Craig Bellamy's opener.
Substitute Andre Schurrle equalised before Torres - in possibly his farewell match, with the Blues rumoured to be prepared to cut their losses on the £50million striker this summer - added a second for his first goal in 12 league games.
It was a performance which must have left Mourinho considering a major revision of the end-of-season report he will present to the Chelsea hierarchy on Monday on a day of goodbyes and potential farewells.
Mourinho says he wants to keep out-of-contract trio John Terry, Frank Lampard and Ashley Cole, who is considering his options away from Stamford Bridge after eight years.
Cole captained Chelsea on what could be his final appearance in the absence of Terry (knock) and Lampard (illness), both of whom are reportedly pondering contract extensions on reduced terms.
The future of Mourinho's much-maligned strikeforce is also in doubt as the Blues boss seeks a prolific goalscorer to lead Chelsea's title assault next term.
Torres missed an open goal after four minutes after being distracted by balloons and Cardiff went in front 11 minutes later.
Bellamy, playing for his hometown club for perhaps the last time, benefited from a huge deflection off Cesar Azpilicueta to beat Mark Schwarzer before Schurrle's introduction sparked a late revival for Chelsea, with the German providing a goal and an assist.
Mourinho may be contemplating more of a summer overhaul than he admits if Chelsea are to challenge for silverware next term.
Cardiff must also regroup, albeit outside the top flight, after a calamitous campaign.
The day began with Cardiff owner Vincent Tan saying he would consider changing the club's colours back from red to blue if City could win promotion back to the Premier League.
The home support repeatedly broke into song - "We're Cardiff City, we'll always be blue" - as they watched their red-shirted team take on a Chelsea side who had hoped to be in title contention on the final day.
Whatever Mourinho's protestations over the officiating in the losses to Aston Villa and Sunderland, the Blues' downfall has been their failure to dispatch the lower half of the table, particularly away from home.
Against a side which had conceded three goals or more in five of their previous seven matches, there was an early demonstration of Chelsea's bluntness.
Torres rounded David Marshall but was swamped by a swarm of balloons and his tame shot on his weaker left foot was blocked by Steven Caulker.
Ground staff burst the blue balloons before the Bluebirds went in front when Bellamy picked the ball up 30 yards out in the left channel and tried his luck, with his left-footed strike deviating wildly off Azpilicueta's backside and wrong-footing Schwarzer.
It was Cardiff's first goal in open play for more than five hours, but it might yet be credited to Azpilicueta as the initial shot might have been heading wide.
Lacklustre Chelsea failed to test Marshall as Mohamed Salah missed the target five times and Oscar and Eden Hazard each failed to convert passes from Cole.
Fraizer Campbell fired over after a mazy run for Cardiff, while John Obi Mikel, booked for a cynical trip on Mats Daehli, avoided a second yellow card for another on Fabio as a disjointed first half came to an end.
The end-of-season fare was little better after the break as Torres blasted wide and Declan John shot straight at Schwarzer at the other end.
Salah had a shot blocked by Azpilicueta and Hazard fired into the side-netting before Schurrle, on for Mikel, equalised.
Oscar's cross into the box was met by Azpilicueta, who was denied by Marshall at point-blank range.
The Spain right-back hit the bar with the follow-up and the ball fell for Schurrle, whose shot into the floor looped over Marshall.
Chelsea had a second when Azpilicueta crossed, Cardiff failed to clear and Schurrle nodded down for Torres, who converted down the centre of the goal.
Hazard was unable to net a Schurrle cross at the far post and Marshall saved well from the Germany forward as Chelsea finished with a win.
Source : PA
Source: PA