The importance of the Manchester derby this weekend really can't be underestimated.
With far more than bragging rights at stake, Jose Mourinho will be well aware that his side have to win this game to halt City's march towards the title.
Both Mourinho and Pep Guardiola need their key men to perform, and Ryan Giggs has highlighted Romelu Lukaku as pivotal to the Red Devils' hopes at Old Trafford - where United have now gone 40 games unbeaten in all competitions.
The Belgian remains the club's top scorer with 12, but he has managed just two in his last 13 games.
The striker is back among the goals following his strike in the 2-1 win over CSKA Moscow, and Giggs has told Sky Sports exactly what he has to do to make an impact against their rivals:
"I think centre-forwards go through droughts and when you're a Manchester United forward the scrutiny multiplies and that was always going to be the case," he said.
"I said at the start of the season Lukaku will be judged on the big games because he'll score goals, there's no doubt about that. The big games are what will define him as a being a really great United centre-forward.
"I think he's really important in this game because when he holds the ball up, like he did a couple of times against Arsenal, we're a different team, whereas when it keeps coming back, like against Liverpool and Chelsea, when he wasn't holding it up, it is just wave after wave of attacks.
"Once he gets that hold up play the rest will come because he is a goalscorer. I was at the Champions League game on Tuesday night and he didn't do a lot but his finish for his goal was really good, so that will give him a big lift because going into this game without scoring the pressure would have been even more."
The 24-year-old is yet to score against a 'big six' side since moving to the Theatre of Dreams.
There are few better games for that to change in.
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