The left-back came on in the second half and quickly racked up a couple of fouls on the Italian, but he insists the striker was out of control and needed to be impressed upon
The Italian forward put in a number of dangerous and wayward tackles in the first half and was lucky to still be on the pitch at half-time.
He was later sent off for a second bookable offence following a tackle on Bacary Sagna, while City boss Roberto Mancini called for the FA to look into handing his player a longer ban for a challenge on Alex Song that went unpunished.
“In the first half Balotelli almost broke Song’s leg, then he harshly tackled Sagna. Someone had to be hard on him, put him in his place,” he told ESPN Brasil.
“Someone had to say something to him because he was doing what he wanted, and that’s not how things work.
“I was watching from the bench. When I was on the pitch I’d have the job to mark him, and that’s what I did. It’s part of the game.”
The 29-year-old had been out of action with an ankle injury for three months but four successive matches as a substitute have given him time to recover his fitness.
“I’m much better, the pace is different, but I’m good physically,” Santos said.
“I’ve trained a lot, I played with the reserves. Man City was my fourth match on the bench, the second I’ve come to the pitch. I’m feeling a lot better, ready to be back to the starting XI.”
Santos also praised manager Arsene Wenger for helping turn the club's fortunes around this season.
“Today our target is getting more within reach with each match,” he continued.
“We have to keep working to hold on to this third place. It’s very hard to get to first but our target is to be in the Champions League.
“Arsene Wenger is a very calm and mature man, he always deals with situations in the same way, whether we are winning or losing. The supporters like him very much; he has credibility at the club.
“I think it was this experience that he has that made us to turn it around.”