Blues boss Roberto Mancini immediately replaced the 20-year-old, so unimpressed was he by Balotelli's conduct, leading to a touchline row that heightened fears about a lack of discipline in the City camp.
However, Beckham, whilst reminding Balotelli of his status within the game, did feel there was a legitimate excuse.
Scroll down to see the video of Balotelli's bizarre attempt on goal
Backing: David Beckham has lent his support to Mario Balotelli over his infamous backheel
'I have watched it back a few times and from his mannerisms I believe he thought he was offside,' said the former England skipper. 'Mario has been a great player for quite a few years and he is still very young. He will continue to get better I am sure.
'But it doesn't matter whether you think it was offside or not. There are a lot of young kids watching these teams and great players who come out here. You have to be professional and score the goal.'
Team-mate Nigel de Jong, though, is still bemused by the Italian's actions.
The Dutchman said: 'I've played with some strange characters in the past but it's the first time I have seen that. It is frustrating, and he has to iron out those issues otherwise it will be a waste of his talent. He has to realise that now.
What were you thinking? Nigel de Jong has led the criticism against his Mario Balotelli
He added in the Guardian: 'All his team-mates are here to help him but he's his own person and he is the only one who can change his ways.'
Beckham will bring his own brand of professionalism to the Red Bull Arena when he appears for the MLS All-Stars in their high-profile encounter with Manchester United.
The 36-year-old will be joined by another former Premier League great in Thierry Henry, who got a playful ear bashing from his new team-mate when he agreed to follow Beckham's lead and carry out an interview with United's in-house station MUTV.
Angry exchange: Roberto Mancini and Balotelli clashed after the striker was substituted in the first half
Not that he is going to be too bothered by angry Arsenal fans for a while as, unlike Beckham who had two short stints with AC Milan during the MLS shutdown in an attempt to maintain his England place, the France striker has no intention of returning.
'Nope,' said Henry, when asked whether he would contemplate returning to Europe as a player. 'I am happy here. I am done with Europe. I was fortunate enough to win everything at club level and now I am happy where I am.
'I am trying to help my team win something, which is very difficult. I respect what David has done but right now, for me, no.'
MLS coach Hans Bakke has already beendealt a blow with the loss of the USA's most high-profile player after Landon Donovan was forced to pull out with a calf injury.
?CLICK HERE TO SIGN UP FOR OUR FREE FANTASY FOOTBALL GAMEHe's infuriating his manager and now even his team-mates are telling Mario Balotelli he risks turning into the Italian yob!VIDEO: Balotelli's backheel and five others who failed to show some R-E-S-P-E-C-T!Evra urges Nasri to shun City's millions for the silverware on offer at United
Source: Daily Mail
Source: Daily Mail