Man i think this is nearly to immposible, but yes if Barcelona failed again for third time in a row to reach the round of 16 they really need to start lloking for a witch, because it seems like a Messi cursed. This year Uefa give thems the most easy group of the history.
I think and really hope that Barcelona is almost at the finish line towards the 1/8 finals. There are a couple of games left that are not that difficult, you just need to put in a little effort and you're done. The most important thing is not to lose points. Barça has every chance.
They should be able to qualify from the group if they look at their chances, the match against Porto will be a home match for Barcelona, they must be able to take advantage of this match very well. If they can win this match then in the last match their task will be easier, as they only need 1 point from that match to ensure they will be in the round of 16.
Assuming, Shakhtar can get 3 points as well, then they will have the same points as Porto (if they lose to Barcelona) thus they (Porto and Shakhtar) will be desperate in their last match, and that's an advantage for Barcelona.
Newcastie is always performing like that and it's up and down. The won against chelsea has proven if newcastle is still strong enough but it will be different when it was about the match in UCL. Newcastle is going to face PSG soon. I don't really think newcastle is in the best shape to beat PSG away. The club really needs to grab three points from PSG. It will determine the chance of newcastle to go to the next round. Newcastle will be also leaving from UCL if it will be failed to gather three points.
I think all of the teams are the same, they will always perform well and bad. No teams that really can perform constantly, they sometimes win the match and sometimes get a lose. Newcastle won against Chelsea with big scores, it shows that Newcastle still have the power to beat any team. They also have the chance to win against PSG, PSG doesn't has a too strong defense. So, we don't know whether Newcastle ton win the match or not. It depends on the situation of the teams in the match.
They will be the visitors when facing Paris Saint Germain, not an easy task for Newcastle in this match. Yes they will get a lot of pressure that will be given by Paris Saint Germain supporters to disturb the mentality of the Newcastle players. The coach must be able to anticipate that, because after all it will be very influential in the game if they are really awkward with the pressure given. The coach must ensure the mental players he has are in very good condition in this match.