For a long time, the gulf in class between Manchester United and Manchester City was massive.

Throughout the first two decades of the Premier League era, there was no comparison between the two clubs.

United were by far the superior team out of the two.

However, that has changed in recent years.

Ever since Sir Alex Ferguson left United in 2013, United have been on the decline, while City have been on the rise.

There is once again a big gulf in class between the two but now it is City that are by far the superior team.

The difference in quality between the two has been expressed in a study from FiveThirtyEight.com.

Using their own algorithm, FiveThirtyEight have been able to rank the best sides in the world.

In their system, every team is given an offensive rating that represents the number of goals it would be expected to score against an average team on a neutral field, and a defensive rating that represents the number of goals it would be expected to concede.

These are then combined together to give every side's SPI (Soccer Power Index) rating.

Their rankings change every week based on every team's performances but, going into the 2019/20 season, Man City have been ranked as the best team in the world.

Bayern Munich are ranked second, followed by Liverpool, Barcelona and Chelsea.

United are ranked all the way down in 34th. Ouch.

View the top 20 below:

1) Man City
2) Bayern Munich
3) Liverpool
4) Barcelona
5) Chelsea
6) PSG
7) Real Madrid
8) Atlético Madrid
9) Olympiacos
10) Ajax

11) Atalanta
12) Tottenham
13) Leverkusen
14) Inter Milan
15) Juventus
16) Valencia
17) Porto
18) Napoli
19) Eibar
20) RB Leipzig

Selected others:

25) Dortmund
26) Everton
28) Arsenal
33) Young Boys
34) Man United
41) Roma

Despite Liverpool beating Bayern last season, the German side are ranked marginally ahead of the Reds.

Chelsea's success in the Europa League sees them in fifth, while Olympiacos are a surprise inclusion in the top 10.

Tottenham got to the Champions League final but their poor end to the season sees them in 12th, while Juventus are surprisingly low down in 15th.

United, all the way down in 34th, are behind sides including Everton, Arsenal, Eibar and even Swiss side Young Boys.

For the full rankings, click this link:

What do you make of the rankings? Have your say by leaving a comment below.