Though he may not be on his absolute top form, Marouane Fellaini has shown in his three appearances for the club that he will be a vital part of their success, or lack thereof.
Aside from having to acclimate to playing with a new team, Fellaini will have to re-reinvent himself as a defensive midfielder after playing just a notch behind the striker at Everton.
The Belgian has mentioned he actually prefers to play defensive midfield over an attacking role (Sky Sports), and he has a point based on the skill set he brings to the table.
Though he will likely not score as much, Fellaini will be able to aid United defensively and aerially, just as he did vs. Crystal Palace and Bayer Leverkusen. In these games, Fellaini was a vital part of United's attacking play but even more so was a stopgap in the attempts of these opponents to get forward.
The big-haired Belgian won an outrageous amount of headers as well as showcasing his strength in the dispossession of opponents.
In addition to his defensive duties, Fellaini displayed the on-ball aplomb that makes him a much more attractive option than the erratic Tom Cleverley. Constantly making the smart passes, the Belgian had an 88 percent average pass success rate through these first two games, via Who Scored.
With a fine attempt at goal vs. Crystal Palace (1:32 in video) and a sublime piece of skill vs. Bayer Leverkusen to control the ball in the center (seen below), Fellaini showed that his hefty transfer fee was also paying for a player who is extremely technically skilled.
With two fine performances, supported by Who Scored ratings of 6.78 and 7.67 vs. Palace and Leverkusen respectively, Fellaini's United career was off to a solid start.
That all changed vs. crosstown rival Manchester City.
In easily his biggest game as a Red so far, and maybe even his entire career, Fellaini's composure was transformed into complacency as he was bested by Yaya Toure in the center.
The Daily Mail's Charlie Skillen explained in his article that though Fellaini was actually better statistically, he constantly chose the predictable pass to the flanks instead of really pressing into City's half.
Meanwhile, Toure converted fewer passes but was more diverse in where he distributed the ball, opening up the field for City and confusing the United defense.
After physically dominating midfielders in his first two appearances, Fellaini took a step back against City and Toure.
In fairness, Toure is one of the world's premier players, but Fellaini's lack of involvement was alarming, and he looked more like a Michael Carrick counterpart than himself with his reluctance to push forward and play physically.
With a place in the starting XI, Fellaini will have his chances to score and beat defenders, but United's plethora of technically skilled players reduces the need for him to do this week in and week out.
What he does need to do every week is the dirty work, which has been neglected in the United midfield since the retirement of Paul Scholes, and which Tom Cleverley and Michael Carrick are not capable of doing consistently.
Even with a poor performance against City, Fellaini has drawn optimism after a decent overall showing in his first three appearances.
West Bromich Albion will meet the Belgian next.
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