When a team is challenging for the Premier League they need to show togetherness throughout the entire season.
Football is a squad game and, as we've seen from sides who've recently won the title, it takes more than just individual brilliance to secure the top-flight crown.
Last season, Pep Guardiola was praised for utilising the majority of his Manchester City squad, with his wealth of options allowing him to rotate without weakening his starting XI.
Chelsea, the champions of Europe, went through a drastic change at the beginning of last season as they went big in the 2020 summer transfer market. Thomas Tuchel is now getting what Frank Lampard should've got out of his squad, and with the addition of Romelu Lukaku, they now have depth in almost every single position - a key factor behind them being most people's favourite for the title.
Manchester United have also drastically improved their squad recently following the additions of Tom Heaton, Jadon Sancho, Raphael Varane and Cristiano Ronaldo.
Throughout United's pre-season, Ole Gunnar Solskjaer stressed that depth would be absolutely pivotal to a successful season, which is why the likes of Jesse Lingard have stayed in order to add competition to those in the starting XI.
"We need a big squad," Solskjaer said before the start of the season.
"The start is important, the whole season is important, but you need to arrive in April and May fresh and with enough options. Some [players] might go on loan until Christmas, some might go for a season but I don’t want to be too light in any position.
"We need to arrive in April and May with players fresh. We need players with X factor who can make a difference. Bruno [Fernandes] last year for example, maybe I overplayed him but it was because he was so important for us. Adding these extra players - Jesse coming back, Jadon [Sancho] coming in, Anthony [Martial] being fit again - it gives us a lot more to work with."
Solskjaer now has a squad capable of competing against the likes of City and Chelsea, but when will find out whether the improvements made to the squad have really made a difference? Well, the hectic Christmas schedule is always a decent indicator.
Generally speaking, if you're top of the Premier League on Christmas Day, you've got a decent chance of going on to win the league.
United's fixtures aren't the worst when compared to their rivals' and they can pick up some crucial points during this part of the season. Arguably, their December fixture list is the easiest when compared to the likes of Chelsea, City and Liverpool.
Is United's squad good enough to win the title? Follow our new United On My Mind writer Omar Garrick on Twitter to get involved in the discussion and give us your thoughts on the matter in the comments section below.