As I said already, I expected Chelsea to walk over Arsenal. It can already be seen what Lukaku will bring to them, they really have a diversified and potent attacking line.
United drawing to Southampton was a bit unexpected but early on in the league results like these happen quite often. Pogba getting another assist, he's already reached 5 in 2 games - if he will have a good season, United will be a serious contender.
This is Arsenal's second defeat I also predicted the same that Arsenal will not be able to fight Chelsea and sure enough Lukaku showed the first goal with a good finishing even if Lukaku was in front of goal he would definitely score.
In the third week Arsenal will be even more difficult because facing Mancity it is clear that this will be another defeat, sometimes the game can change but I don't think Arsenal will be able to win at Mancity.
And Chelsea vs Liverpool will be more exciting.