Roberto di Matteo make it two wins in two in charge of the Royal Blues as his side came from behind to edge a seven goal thriller in Gelsenkirchen on Tuesday.
Hopes were high after a 2-0 victory over Hertha Berlin on the weekend, though former Manchester United winger Nani put the visitors in-front after just 16 minutes to unease the Gelsenkirchen support.
However, a red card for Mauricio and then an Obasi equaliser looked to have put the game well in Schalke hands at the break, before Huntelaar and Howedes looked to have sealed the game beyond doubt by the hour mark. However, Silva slotted home a penalty to reduce the deficit, before scoring again, a goal which looked to have sealed an unlikely draw for Sporting.
More drama was yet to come though, as Choupo-Moting scored a 93rd minute penalty to give his side a win which kept them as favourites to qualify behind Chelsea.
The Portuguese side - fresh from a 3-1 victory over FC Porto in the league last week - started the better, Nani looking sprightly as he curled an effort just wide early on with Fahrmann grasping air.
Hoger then drove a shot straight into the hands of Patricio, as the hosts looked to have taken an early foothold on proceedings. Just minutes later though, that all changed, when Nani struck a venemous effort from inside the area, which went almost through Huntelaar and then through the legs of Fahrmann to put the away side in front.
Julian Draxler nearly levelled almost immediately, when Obasi found the winger with a floating ball, though the German saw his effort fly just the wrong side of the woodwork.
It was the Bundesliga side who took charge though, and it paid when Mauricio received two yellow cards in 14 minutes for fouls on Huntelaar and Hoger to give the Germans a huge lifeline.
That lifeline was taken just two minutes later, when Aogo's deep costless-kick was headed towards goal by Obasi, and Patricio spilled his header into the net.
Choupo-Moting came on for Boateng at the break, as di Matteo looked to take the game to Sporting, and their reward came just minutes into the second period. It was the substitute Choupo-Moting who latched onto Draxler's ball, before sliding it into Huntelaar who expertly found the corner to make it 2-1.
The game looked to be done and dusted on the hour, another set-piece troubling the Portuguese side, with Howedes this time getting on the scoresheet, heading home Ayhan's pinpoint cross.
Ayhan went from hero to zero though as he gave the visitors a chance to get back into the game when he hauled down Carrillo just inside the 18. Adrien Silva stepped up, and scored a penalty which gave his side a glimmer of hope.
Whilst they pushed for the equaliser, space was left open at the back, and the game really should've been up when Choupo-Moting chose the wrong option as The Royal Blues broke with four-on-three.
Heartbreak ensued with 10 minutes to go, as Sporting looked to have rescued the point. Pressure was mounting on the Schalke goal, and Cedric found Silva with a cross, leaving the 25 year old to slot home the sixth goal of this epic encounter.
Sidney Sam came on for Draxler in the final moments, and as the official held up three minutes of injury time, the Germans believed again. It took until the last of those three to make Sporting pay, when bold appeals for handball were rewarded, as the official behind the goal confirmed the spot-kick - despite replays clearly showing the ball struck Silva's face.
Choupo-Moting became the hero, as he found the corner and gave his side the win, and provided the final twist in one of the greatest Champions League fixtures of modern times.
The win puts Schalke second with five points from three games, while Sporting remain bottom with just one point, and face a huge task to qualify from here, as they still have to travel to Stamford Bridge.