The striker, who so often has appeared burdened by his £50m price tag, netted a scrappy opener after 16 minutes and headed a second after 70 minutes to double his tally for 2013, while Victor Moses was also on target for the Blues.
But the first leg was not altogether straightforward for last season’s Champions League winners as Bebras Natcho converted a penalty after John Terry was adjudged to have blocked a shot with his arm.
Chelsea are well placed to advance to the last four in Moscow’s Luzhniki Stadium – the scene of their 2008 Champions League final penalty shootout defeat to Manchester United – but the away goal could yet have a crucial bearing on the outcome.
It means Chelsea’s leading players must travel to Russia next week ahead of the Wembley FA Cup semi-final with Manchester City.
Chelsea interim boss Rafael Benitez will be content with the result and the performance of Torres, in particular.
“It’s good for his confidence,” said Benitez.
“His work-rate was really good. I’m pleased for him.
“I have said before, he’s training well. It was a question of time. He scored two goals today and hopefully it will be the same in the next game.”
Chelsea’s immediate attention now turns to the quest for a Barclays Premier League top-four place and Sunday’s fixture with Paolo Di Canio’s Sunderland.
Last night’s clash was no stroll, however and having already eliminated Europa League holders Atletico Madrid, Rubin Kazan were seeking to add last season’s European Cup winners to their list of scalps and travelled to London unbeaten away from home in the competition.
But the Blues were patient in the opening 15 minutes before the direct route paid off when David Luiz’s ball from deep found Torres, who was playing in a protective face mask after suffering a broken nose against Steaua Bucharest in the previous round.
The Spaniard managed to sneak in behind Rubin captain Roman Sharonov and the pair fell tussling for the ball. Torres managed to connect while sitting on the floor to prod the ball in for his third goal in 23 games and first since the home defeat of Steaua.
Natcho tested Petr Cech from 25 yards for the visitors before Chelsea doubled their advantage.
Cesar Azpilicueta crossed from the right and Moses’ bouncing header was well saved, but the ball came back to the forward, who struck a swerving half-volley into the top corner.
There was a moment of concern for Chelsea when Cech caught Vladimir Dyadyun with an elbow when meeting a long ball before referee Gianluca Rocchi pointed to the penalty spot after Cristian Ansaldi’s shot hit Terry on the arm.
Terry’s arm appeared to be in a natural position when the ball struck it, but he was booked and Natcho sent Cech the wrong way to claim a potentially crucial away goal to the delight of a group of around 50 visiting supporters.
But their joy was short-lived when Mata found Torres with a neat cross and the latter converted with a powerful header. Advantage Chelsea.
CHELSEA: Cech, Azpilicueta, Terry, Luiz, Bertrand, Ramires, Lampard, Moses (Hazard 65), Benayoun (Marin 83), Mata (Oscar 78), Torres. RUBIN KAZAN: Ryzhikov, Cesar Navas, Kuzmin (Kasaev 82), Kaleshin, Ansaldi, Sharonov, Orbaiz, Roman Eremenko, Karadeniz, Natcho, Dyadyun (Rondon 46).
Referee: Gianluca Rocchi (Italy).