Lukaku escaped any sanction despite television footage appearing to show him aiming a kick in Bong's direction during United's 1-0 victory on Saturday.
The footage was reviewed by a three-man panel made up of former Premier League referees, which did not unanimously agree that the incident warranted a red card - which would have resulted in a three-match ban to rule him out of United's upcoming Premier League matches.
If the FA chose to charge the Belgian striker, he would have been banned for three games; United's trip to Watford on Tuesday, their visit to Arsenal on Saturday and the Derby against Manchester City eight days later.More news: Saoirse Ronan's Lady Bird tops Rotten Tomatoes rating
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A Football Association panel decided no retrospective action was required.
"As soon as I saw it, I thought they will probably look at it".
Though Watford were trounced 6-0 by City in September, they have doled out some bloody noses on their home turf, holding Liverpool to a 3-3 draw in their first game and beating Arsenal 2-1 last month. And unfortunately not every player is the same.
"Some guys are capable to go into the limits of their efforts and some other guys even with a lot of talent, they don't manage to do that. Didn't score, I don't care".