Marseille so far still looks great in ligue 1 and they managed to get a win without losing even once like PSG who are at the top of the standings, we admit their performance in the league is still much better than in the champions league and I think it is difficult for marseille to come out from the group phase champions league, now it seems better for marseille to focus on ligue 1 than them chasing the champions league which is indeed very difficult to get for a team like marseille,good performance in ligue 1 at least put pressure on PSG although maybe it won't last long .
Marseille is a fickle team, I mean they can't be expected to be stable all the time because the quality of the team is almost the same as many other teams in Ligue 1. PSG won't be under much pressure from Marseille especially as it's still early in the season with 7 match. You probably know that Marseille's form will decline over time, and I don't think that's ever surprising to look forward to.
If Marseille can maintain this good form in the many match to come including when they away to PSG, then I can say they deserve to be strong contenders for the title. But it is something that is difficult even though until week 7 they are unbeaten.