Liverpool are currently the top contender for the championship. I assume most people share the same opinion as me. 
They are currently the only team without a loss and winning 6 out of 6 games so far.
However it is still too early to be very confident about something of course. This is only league phase. Even the top teams not performing very well these days can start playing much more differently later on. Such as Real Madrid.
Besides I believe Barcelona also have a quite big potential here this time. Hansi Flick's system works very well in the Champions League too as far as I can see.
Do not look now to determine it, because we know this is only in the early phase and not yet to the next round even though Liverpool has a series of wins without losing they will still continue to fight to the next round. They are currently the only team without a loss and winning 6 out of 6 games so far.However it is still too early to be very confident about something of course. This is only league phase. Even the top teams not performing very well these days can start playing much more differently later on. Such as Real Madrid.
Besides I believe Barcelona also have a quite big potential here this time. Hansi Flick's system works very well in the Champions League too as far as I can see.
Liverpool are experiencing poor results in the Premier League, hoping this does not affect their play in the Champion League and it is certain that in this phase Liverpool will qualify.
Now in the next phase, we don't know which team will meet so it will be a tough challenge again.
The champions league is a totally different atmosphere all together and many teams can attest to this because I have seen many teams that have performed poorly in the premier league but when they get to the champions league the whole form changes and I think Real Madrid is one of those teams. For now even if the draws for the round of 16 comes out I think Liverpool can take on any of the big teams because they have shown that they are stable enough.