What an unfortunate results for Arsenal and Liverpool.
But, Liverpool is still better than Arsenal. Liverpool lost one player and they can score 2 goals, while Arsenal playing with full team and in their home, can't beat Everton, a team that weaker than Fulham. I think Robertson did that because they were behind one goal, so he take a risk to not conceded 2 goals.
Liverpool played with only 10 players in most time of the match and they tried hard to win it. If they were lucky enough, they could win this match even with disadvantage of only 10 players. Arsenal are different, they played with 11 players against Everton, created opportunities but their weakness in attacking system costs them 2 points. In this match, again Arsenal shows that they lack of a good striker who has good ability to convert key passes to goals. This weakness can cost them Premier League title again. Liverpool drop points but Arsenal fail to take advantage of it to reduce point difference to 4, and they already played 1 match more than Liverpool.
Yeah Chelsea is the strongest competitor in this season, I laugh when people underestimated Chelsea will not become a champion and they can only finish at top 4. Chelsea will meet Brentford, I'm sure they will win.
Chelsea is a big surprise and now they are only 5 points less than Liverpool with similar total matches. They have 1 point more than Arsenal but they can expand it to 4 points with one match in hands. It's interesting if Chelsea manage to enter the title race with Liverpool while Arsenal and Manchester City will compete for top four, or more exactly last two positions in top four.