As Manchester United's major summer signing, the pressure has been on £27.5m Marouane Fellaini to hit the ground running.
After an encouraging cameo against 10-man Crystal Palace, Fellaini made his first start against Bayer Leverkusen and was reasonably impressive as United ran out 4-2 winners at Old Trafford. But, in truth, David Moyes' men rarely looked troubled by their Bundesliga opponents and probably would have sealed the three points even without the Belgium international.
Then came his first big test since completing his move from Everton on transfer deadline day: a trip to the Etihad Stadium to take on City in the first Manchester derby of the new campaign.
The result wasn't pretty for United or Fellaini who, rather than a 6ft 4in powerhouse, was made to look like a lost little boy by Yaya Toure.
United were thrashed 4-1, and Fellaini was subsequently left out of the team for the club's next two matches against Liverpool in the Capital One Cup and West Brom in the Premier League.
Rather than punishment for his poor performance - he wasn't the only United player to perform badly at the Etihad Stadium by any stretch of the imagination - this was almost certainly a ploy by Moyes to get Fellaini physically and mentally ready for tonight's Champions League group stage match against Shakhtar Donetsk.
Make no mistake, this fixture is a massive test for both Fellaini and Moyes, who have never participated in a Champions League away tie before.
Moyes knows that avoiding defeat against the Ukrainian champions at the Donbass Arena is imperative - not only to bounce back from Saturday's shock defeat by West Brom but also to keep the Red Devils on course to qualify for the Champions League knockout stages.
Another defeat would also leave the media - and maybe a few disgruntled supporters - sharpening their knives for the Manchester United manager.
In order to prevent that from happening, Moyes will need his powerful central midfielder to be on top of his game to stifle and frustrate Shakhtar's attack-minded players, while a goal would do his confidence the world of good and simultaneously help endear him to the United faithful.
Fellaini cannot simply blend into the background at United. After costing almost £30m, it's up to him to make sure he makes the most of this golden opportunity to play for England's most prestigious football club by taking games like this by the scruff of the neck.
Moyes may be afforded time to adapt at Old Trafford, but Fellaini will have less - and he must start justifying that hefty price tag as quickly as possible.