Goals at the start of each half from Mehdi Taremi and Moussa Marega earn Porto a shock victory over Juventus.
With only two minutes on the clock, Mehdi Taremi capitalised on a defensive error to put his side ahead, before Moussa Marega doubled the advantage at the start of the second half.
Federico Chiesa pulled one back in the 82nd minute, and Juve had a penalty shout in added time when Cristiano Ronaldo went down in the box, but the referee did not award the spot-kick.
Erling Haaland continued his Champions League scoring run after his brace gave Borussia Dortmund a 3-2 win over Sevilla.
The Spanish side took a seventh-minute lead after a Suso shot deflected in off Mats Hummels.
Mahmoud Dahoud then scored a stunning equaliser before Haaland struck twice in 15 minutes inside the first half, taking his tally to 18 goals in 13 games in the competition.
Luuk De Jong came off the bench to score in the 84th minute to give Sevilla hope.