Galatasaray started brightly and took the lead inside six minutes when Lucas Torreira finished a bizarre move following a throw-in. The midfielder's effort initially appeared to involve Gonçalo Inácio, with the goal ultimately recorded as an own goal against the Sporting defender. Goal-line technology confirmed that the ball had crossed the line.
• Sporting CP: Geny Catamo 27', Luis Suárez 57' (pen), Rodrigo Zalazar 63'
• Galatasaray: Gonçalo Inácio 6' (og)
The Portuguese hosts gradually recovered from their poor start and equalised in the 27th minute. Geny Catamo controlled the ball inside the Galatasaray penalty area before firing beyond Uğurcan Çakır to make it 1–1.
Sporting continued to grow into the contest before the break, although Galatasaray had enjoyed the better start and created opportunities through their attacking players. The two sides went into half-time level.
The decisive moment arrived nine minutes after the restart.
Luis Suárez was brought down inside the Galatasaray penalty area after being played through by Issa Doumbia, giving Sporting a chance to complete the comeback from the spot. The Colombian striker stepped up himself and sent Çakır the wrong way to put Sporting 2–1 ahead in the 57th minute.
Galatasaray struggled to regain control after falling behind, and Sporting punished them again six minutes later.
Rodrigo Zalazar produced one of the outstanding moments of the night, curling a powerful direct free-kick into the top corner from the left side to extend Sporting's advantage to 3–1.
Okan Buruk attempted to change the game with his substitutions, including the introduction of Rafael Leão and İlkay Gündoğan, but Galatasaray could not find a route back into the contest. Sporting remained comfortable during the closing stages and saw out the victory.
The defeat leaves Galatasaray without a point from their opening Champions League fixture, while Sporting begin the league phase with three points. UEFA's fixture list shows that Galatasaray's next Champions League match is a home meeting with Barcelona on October 13, while Sporting travel to Lens on the same date.
For Galatasaray, the result will be particularly frustrating after taking an early lead and controlling significant portions of the opening half. Sporting, however, showed greater efficiency after the interval, with Suárez and Zalazar providing the decisive quality to complete an impressive comeback.