The Italian striker with a hot-headed reputation scored the lone goal in regulation for City but was relegated to the showers by the time the teams went to a penalty shootout to decide the exhibition match.
Mancini was incensed after Balotelli broke in on the Galaxy goal in the 28th minute and then turned backwards and tried to hit a ball into the net with the back of his foot. The ball went wide and Balotelli was pulled from the game as soon as his replacement could warm up.
"I think for the player, this can be a lesson," Mancini said. "This can't happen on a strong team.
"I hope he understands that he needs to have good behaviour."
Goalkeeper Joe Hart made the game-winning penalty kick as City beat the Galaxy 7-6 in a penalty shootout in the friendly football.
Balotelli, who has been criticized before for his unprofessional antics, was replaced by James Milner.
Once on the sidelines, Mancini and Balotelli got into it. Mancini appeared to motion for Balotelli to head to the locker room but Balotelli extended his arms, said something and then sat down on the bench where he slammed a cup to the turf and took off his jersey as he watched the rest of the half. He stayed in the locker room for the second half
Mancini told reporters after the match that the situation is under control and there is no need to take it any further.
The temperamental Balotelli has a checkered past. Three months ago he got into a row with Manchester United players at the end of a FA Cup semi-final match. Balotelli had to be dragged away from the scrum that ensued after the Italian's spirited victory celebration angered the United players.
In March, Balotelli was investigated by the club after a claim he threw a dart at some youth-team players at the club's training facility.
Three months earlier, Mancini has to break up a fight between Balotelli and Jerome Boateng after Balotelli reacted angrily to a challenge by his teammate during a training session.
The win over the Galaxy was the third straight for Manchester City in their North American tour. It went to the shootout because of the regulations of the World Football Challenge friendly tournament which the match is a part of.
Hart stopped an AJ DeLaGarza's penalty kick then stepped up to take his turn in the shootout after the teams battled to a 1-1 draw in regular time.
Galaxy's Mike Magee scored in the 53rd minute to tie it 1-1, hitting a perfectly place shot from outside the box that Hart couldn't get to.
"They're a good team, so we knew it would be a good test for us," City midfielder Milner said. "But that's what you want for preseason, a good test, good fitness. All-in-all, it was a good game."
Manchester City used their starters for most of the game as the get ready for the upcoming Premier League season.
Source: AFP
Source: AFP