Goal difference only matters if you are level, so we shouldn’t look at goal difference as it currently is but what it will be if teams get the results that will lead to them being level on points and we know certain things about all those situations.

Something that is often missed in commentary when discussing goal difference is that in order to gain three points on your rival on the table, a goal difference swing of at least +2 is required. In order to gain 3 points on your rival, you have to win and your rivals have to lose (or there can be a combination of results involving draws over multiple matchweeks but that doesn’t change the maths). In order to win a match, you have to score at least one more goal than you conceded meaning you will get at least +1 goal difference. The opposite applies for your rival when losing meaning they will get at least -1 goal difference. This is a net change of +2 GD in your favor.

Since a draw means no change in goal difference and you gain one point on your rivals if they lose and you draw, and you gain 2 points if they draw and you win, therefore it means that gaining 1 point, 2 points, or winning a game in hand nets you at least least a net change of GD of +1.

**What this means:** City can level Arsenal on points in the next two matches if they beat Arsenal and then win their game in hand. If that happens city will gain at least +2 from those two wins, and Arsenal will get at least -1 from their one loss. If city only wins those games by 1 goal each then both teams will be on 70 points, and each team will be on a goal difference of +37, meaning the tiebreaker will go to goals scored which currently favors city and cannot flip in the next two matches with two city wins as it implies City will out score Arsenal by at least 1 and out score their opponent. Meaning City despite having the points disadvantage and being behind in goal difference, currently has a very small advantage in a tiebreaker scenario. And meaning City winning their next two games will guarantee them being on top of the table in a week and a half from now.

**Two things that are worth noting** *(Though this involves a lot of different hypotheticals that’s hard for me to layout clearly so if something is confusing then feel free to ask me to clarify or just ignore all this):*

Firstly, that this current advantage remains true no matter what series of results leads to them leveling Arsenal on points. If Arsenal beat city then that would widen Arsenal’s point lead by 3 to +9 and their goal difference lead by at least 2 to +5. If City lose their game in hand then Arsenal’s points lead will remain at +9 and City will go down at least-1 goal difference making Arsenal’s goal difference lead at least +6. But we know that in order to gain 3 points on your rival it will require a goal difference swing of 2, so if City then win 3 more of their remaining fixtures and Arsenal lose 3 of them, then City will gain +6 goal difference meaning City have this current tie breaker advantage in any scenario where they end up level.

Secondly, despite this, the advantage changes completely as soon as someone wins by more than 1. While City are guaranteed to be in first in a week and a half if they win their next two games, they can still obviously lose on goal difference by the end of the season if Arsenal win all their remaining games by 1 goal except one that they win by 2, and city only win their remaining games by 1 goal. City’s goals scored lead is even more fragile as you can increase your goals scored regardless of result, so if City wins their next two by one goal each to make goals scored the tie breaker, City and Arsenal could lose every game for the rest of the season 0-1, but if Arsenal then just loses their very last game 3-4 then they would win the league by losing with the same margin as City. If Arsenal lose their game after city by 19-20, or tie it 19-19, or win it 19-18 then they will have an essentially insurmountable goal scored difference, if other results make it relevant. So essentially while a goal difference change between rivals always moves in the same direction as a points change, a goals scored change does not have to. The only reason we know City’s will hold over the next two games is because they are playing Arsenal and then they play without Arsenal playing.

So all of that said, if City catch Arsenal on points, then we are in for a major shoot out, as both teams will be close to completely tied and both will be trying to out gun each other in their remaining fixtures.