The Lisbon club have been rewarded for their combative performance against the Premier League leaders and take a narrow lead to the second leg next week
A classy backheel finish from Xandao early in the second half proved the difference between the two sides, as City failed to prove their credentials against a well-organised home outfit. Ricardo Sa Pinto's team created the best chances of the match, and only Ricky van Wolfswinkel’s nervousness prevented Sporting from taking a bigger lead to Manchester.
The hosts were first to create danger just three minutes into the game, when Daniel Carrico tried to find Van Wolfswinkel with a long ball, forcing Joe Hart to leave his place between the posts to nod away. The clearance fell into the path of Stijn Schaars who tried to chip it over the goalkeeper, but his effort went just wide of the goal.
City then suffered a heavy blow, as Vincent Kompany picked up a muscular injury. With the visitors momentarily down to 10 men, Sporting surged forward and almost scored in the ninth minute, but Hart punched away a Joao Pereira shot from inside the box.
Kompany eventually had to be replaced, and in the 11th minute, City went close to scoring for the first time, as Aleksandar Kolarov whipped in a cross from the left after a corner was played short. Kolo Toure rose unchallenged in the six yard box, but his header was denied by Rui Patricio's right leg.
The match was being played at a slow pace, with neither side able to stamp their authority on the game, but every time that City upped the tempo, they created Sporting all sorts of problems.
Sporting began the second half the brighter and opened the scoring in the 50th minute through Xandao. Joe Hart tipped away a free-kick from Matias Fernandez into the path of the Brazilian defender, who clipped home a backheel finish on the rebound after his first shot had been blocked by the goalkeeper.
The hosts were now in control of the game, and they almost doubled their lead in the 62nd minute. A Schaars pass opened City up on the left side of the box, where Insua, with plenty of room to operate, played the ball back to Van Wolfswinkel, whose shot from close range went straight against Joe Hart.
Mario Balotelli came on for Edin Dzeko in the 70th minute, and the Italian striker almost caused an immediate sensation, running down the left side of Sporting's box before cutting a low pass into the middle for David Silva, but the Spaniard’s shot went wide of the left post.
Aguero almost equalised in the 89th minute after finding himself in a one-on-one situation with Patricio, but the Argentine's chip over the goalkeeper was cleared by Xandao.
The result gives Sporting a narrow lead for the return leg in England, on March 15.