Having seen Manchester United follow Arsenal and Manchester City in losing their last-16 first-leg ties 2-0, the west Londoners refused to wilt under the intense pressure brought by the raucous Turk Telecom Arena crowd.
The Blues had looked on course for victory after Torres netted in a dominant first-half display, only for Roberto Mancini’s side to produce a much improved performance after the break and earn a draw as poor defending from a corner allowed Aurelien Chedjou to strike home.
This was a match of many a sub-plot, varying from Chelsea favourite Didier Drogba facing his former club for the first time to former Manchester City boss Mancini coming up against Mourinho, the man who succeeded him at Inter Milan.
However, the build-up focused on trouble in Istanbul as anti-government protests followed a night in which Chelsea confirmed their fans were involved in two incidents, with police warning the 1300 travelling contingent that it was “not safe” for them to use the Metro to and from the ground.
It was far from the ideal preparation — nor was the leaking of private comments from Mourinho on Samuel Eto’o and his strikers — although those who made the trip could have few complaints about the manner in which Chelsea started.
Chelsea began the match ferociously and were seemingly unmoved by intimidating surroundings.
If anything, it was the hosts looking shaken and Fernando Muslera almost handed the visitors a fourth-minute lead with a wayward clearance, only for the Galatasaray goalkeeper to react quickly to block Willian’s strike.
Mancini recognised his side’s slow start: “We started with a lot of respect for Chelsea and we shouldn’t have that respect. We should have been more aggressive”
Chelsea soon ensured the home side did pay for standing off them. Andre Schurrle slipped Cesar Azpilicueta behind former Arsenal man Emmanuel Eboue and the Spaniard pulled back for countryman Torres, who opened up his body to slot home.
Drogba, involved at both ends in the early exchanges, wasted a chance to level as a poor touch allowed Petr Cech to intercept, with Izet Hajrovic then lashing wildly over.
The hosts mustered their first shot on target in the 30th minute, but Cech was more than a match for Hajrovic’s low shot — the winger’s last action before being replaced by Yekta Kurtulus. It began an improved spell for the hosts, with Cech tipping an Alex Telles drive around the post before Galatasaray saw a goal disallowed in bizarre circumstances.
Burak Yilmaz thought he had struck the home side level from an acute angle, only for the goal to be chalked out as two balls were on the pitch.
John Terry retreated with the ball having conceded a throw-in, only releasing it as Gala took a quick throw-in from which the Turkey international lashed home.
The Blues skipper was booked for the incident and booed off the field at half-time, with only Muslera’s fine reactions denying Torres turning home after fine Eden Hazard pass six minutes after the restart.
However, Galatasaray were now on top and Selcuk Inan hit the post from close range in the 63rd minute after Drogba nodded a header across goal.
It was a warning shot across the bows and one the Blues failed to heed.
Wesley Sneijder sent over a corner two minutes later and, with Branislav Ivanovic wrestling Drogba at the back post, Chedjou lost marker Terry to volley home unmarked as the stadium erupted.
Drogba was replaced to a loud ovation by Umut Bulut as the match entered the final 10 minutes, but poor finishing ensured there would be no more goals.
Chelsea boss Mourinho will know his side are now favourites to progress.
He said: “This is Turkey, this is Istanbul, this is Galatasaray. The first half the game was our game, we had chances to win the game. I can’t complain, my players were fantastic. The second leg will be difficult, all I ask is that Stamford Bridge can give us 10% of what this public gave to Galatasaray.”
One man the blues will have to watch in that return is their old boy Drogba. He said: “Chelsea are the better team on paper but second half we showed we can create them some problems.
“Now we have to go out and do it at Stamford Bridge.”
GALATASARAY: Muslera, Alex, Balta (Kaya 46), Chedjou, Eboue, Sneijder, Inan, Felipe Melo, Hajrovic (Kurtulus 31), Drogba (Bulut 79), Burak Yilmaz.
CHELSEA: Cech, Azpilicueta, Cahill, Terry, Ivanovic, Hazard (Oscar 90), Lampard, Ramires, Willian, Schurrle (Mikel 66), Torres (Eto’o 68).
Referee: Carlos Velasco Carballo (Spain).