I think Liverpool's victory over Arsenal is absolutely crucial. Besides getting three points, it also provides a great start to their second match. Liverpool and Arsenal will face each other again, so winning the first match would certainly be a huge advantage. Therefore, Liverpool will benefit from this. Therefore, if you say that a Liverpool victory over Arsenal isn't important, you're wrong. As Luzin said, all matches are important, and I agree with that. Winning every match in the Premier League earns points, and those points are what will lead a team to the championship.
Furthermore, if you think Arsenal can overtake Liverpool, it's possible. The Premier League is just starting, so anything can happen. However, I personally believe that even though Arsenal has performed well this season, Liverpool will perform even better. Moreover, as we know, Arsenal has consistently experienced a decline in performance as the league draws to a close for several seasons now. So, it's possible that this could happen again this season. With that in mind, I think Liverpool remain strong contenders for the title.
While I agree it is of course a great thing to get three points in any game. I do not think that this decides anything. Arsenal needs to do great for the rest of the season of course, but they still have that chance and because of that I do not see this being any issues at all. We should of course try to make sure that we can make some wins from Arsenal.
Betting on this league will be pretty easy this year, I am going to bet on the favourites at the top, and most probably they will win. Parlay is even a good idea, imagine doing that for Liverpool, arsenal, Chelsea and city. Sure, they won't win all together every week, but even if they do every 3 weeks or so, that would be huge profit by the end of the season and that looks possible.