Defending champions Sporting headed north to Porto for what will likely be their final shot at the title, six points back from the leaders in a league where the big three rarely lose.
Things started brilliantly for the side from Lisbon, going two goals up in the first half, beginning with a header from Paulinho before a stunning passing move from one box to the other was finished by Nuno Santos.
Porto, clearly reeling from the departure of star player Luis Diaz to Liverpool, struggled to get in the game, before one to watch Fabio Vieira cut the deficit.
At the start of the second period Porto then had a huge helping hand from another player with Liverpool connections, as former Red turned Sporting captain, Sebastian Coates, was sent off for a second yellow.
The Uruguayan reached peak s***housery with the longest time-wasting walk off you'll ever see in the 49th minute, but was later left red faced when when Porto equalised and his side needed more time to find a winner.
Vieira, 21, was at it once again with a sublime cross onto the head of Mehdi Taremi for the game's equaliser, but things got nasty late on.
Porto piled on the pressure after their 78th minute leveller, looking to end the title there and then, but some heroic defending and even more incredible time-wasting kept the game level.
That wasn't the end of the drama though, with Portuguese great Pepe left on the opposition goal-line after a heroic last ditch clearance, a major scuffle ensued as the referee blew up for full time.
Substitutes and staff flooded onto the Dragao pitch to protest at referee João Pedro Pinheiro, but the man in black was having none of it.
Circling around a cabal of players and staff, the official picked out four players for red cards after the final whistle, with Pepe crucially suspended amidst the mayhem.
Sporting left everything on the pitch under up-and-coming star manager Ruben Amorim, which may delight City fans, but the quality they showed in the first half possibly won't.
The Lions may be falling short in the title race, six points behind Porto with 12 games to go, but the spirit they showed away at a side on an 11 game winning streak could bode well when City travel to Lisbon on Tuesday.