At this point, Lukaku and Rooney have the same amount of Premier League goals.
Manchester United start the game trailing league leaders Man City by 11 points.
Lukaku was to blame in the build-up to both of City's goals on Sunday and questions are starting to be asked.
The Belgium worldwide has endured a hard spell at Old Trafford over the past couple of months following a return of two goals from their last 13 games in all competitions to prompt criticism of the Red Devils striker.
"I remember a couple of battles in the tunnel, one with Chelsea when I first broke through, then the Arsenal one with the pizza throwing".
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Romelu Lukaku will get 20 goals this season but I don't see him scoring key goals.
Lukaku had the chance to grab a late equaliser against City at Old Trafford but failed to beat Ederson from close range.
Lukaku scored against Newcastle United and CSKA Moscow to threaten to end his poor run of form but the Manchester United centre-forward has continued to struggle with a lack of confidence under Jose Mourinho.
His next opportunity to get back on track could come against Bournemouth on Wednesday, with Mourinho having previously spoken of his unwavering belief in his leading marksman.
Likewise, those chances have not been so easy to come by in recent months, as United have been without Paul Pogba, who was out with a hamstring injury between September and mid-November and then missed the City match after he picked up a red card against Arsenal on December 2.