It was also from that corner, which Brighton could only half clear, that an effort from Ashley Young deflected off the unfortunate Lewis Dunk to record the only goal.
Mourinho is unconcerned about such a drought, however, praising Lukaku's work ethic after newly-promoted Brighton provided what he described as probably the toughest test his second-place team have had all season.
As for Man City, they rallied from 1-down at Huddersfield on Sunday to win the match 2-1.
"Lukaku was impeded as the corner came in but his reaction was extreme, kicking out first with his right foot and then making full contact with his left foot somewhere quite painful".
Lukaku's scoring form has dried up since an electric start to life at Old Trafford in which he scored 11 goals in his first 10 games-his effort in the 4-1 win over Newcastle United on November 18 is his only strike since September.
The incident was missed by referee Neil Swarbrick, meaning that the Football Association (FA) were permitted to intervene and reviewe the evidence provided it was also omitted from his post-match report.
Lukaku is an extremely lucky boy and I'm sure Jose Mourinho and Manchester United were expecting a charge brought against their striker.
If there is no mention of the incident in Swarbrick's report, the FA can still independently look at the footage and make a retrospective decision. Runaway leaders City travel to their bitter rivals on 10 December.