Both clubs are two of the biggest brands in global sport, have multi-millionaire owners behind them and have some of the strongest fan-bases in the Premier League.
So, the fact that both teams were scheduled to face each other on the opening day of the season had everybody rubbing their hands together with excitement.
There were just so many storylines going into the game, no less than the fact two clubs legends - Ole Gunnar Solskjaer and Frank Lampard - were sat in the opposing dug-outs.
However, there was also great interest in the two starting XI's and that was all down to transfers for United as well as the inability to complete any for Chelsea.
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Man Utd vs Chelsea
The Red Devils handed Harry Maguire and Aaron Wan-Bissaka their full debuts, whereas Chelsea invested their trust in youth with players like Tammy Abraham and Mason Mount.
In truth, while some of those players could go on to become star performers, it made for two of the most underwhelming United and Chelsea line-ups that we've seen in the Premier League.
We aren't alone in thinking that either, because a tweet has been doing the rounds comparing how the United and Chelsea teams have evolved in the last 11 years.
How the teams have changed
Back in 2008, the two English giants were locking horns in the Champions League final, which United infamously won after John Terry's penalty shootout slip.
And now Twitter user @purplemus has compared the line-ups for both teams on that famous night in Moscow to the two youthful outfits appearing at Old Trafford this season.
The difference is clear for everyone to see and the shock is evidenced by over 2,000 fans re-tweeting the caption of 'Good Lord.' Check out the full comparison here:
How the great have fallen.
We're inclined to think that Jorginho and Mateo Kovacic are given a hard time by fans, but they look like Sunday League footballers compared to Claude Makelele, Michael Ballack and Lampard.
Similarly, there's a lot of potential in Marcus Rashford and Anthony Martial leading the line together; they just don't hold a candle to Cristiano Ronaldo and Wayne Rooney.
It all goes to show how Chelsea and United have fallen from the two most dominant teams in English football to sides that could fall short of the Champions League places.
It's fair to say that Solskjaer and Lampard would wish they had Didier Drogba and Paul Scholes in their respective teams. Ah well, Scott McTominay and Ross Barkley will have to do.
Who do you think will finish higher in the table - United or Chelsea? Have your say in the comments section below.News Now - Sport News