A win would have seen City join rivals Manchester United at the top of the table but they missed several gilt-edged opportunities to take all three points against a spirited Hammers.
"This is football," Mancini said. "I think that a player like Balotelli, when he has a chance like today, he should score. Because when you are a top player, if you have a chance, you should score this - but I don't think he didn't want to score."
Mancini admitted his side lack a cutting edge in attack, despite naming strike trio Balotelli, Edin Dzeko and Carlos Tevez in the starting line-up for the first time.
The Upton Park blank was the first time in seven months that City failed to register a goal in a Barclays Premier League fixture but Mancini thought his side had done enough to win the game.
"No, no. Not a fair result," he said. "When you have 65% ball possession, 22 shots - maybe less shots on goal - you deserve to win - and we missed four incredible chances to score.
"But I am happy with the performance, because we played well, I'm unhappy with the chances that we're missing. When you're playing well and you have a chance, and you're missing an incredible chance, you can be frustrated...but this is football. If you don't score, you can't win - we lost two points."
West Ham manager Sam Allardyce disagreed with Mancini's take on the result and felt his team were good value for their point. "I'm really pleased," he said. "I think that our performance today from start to finish was very, very good indeed.
"The way we started the game was bright, trying to see if we could test Man City early on. Of course, we did that with a fantastically-taken goal by Kevin Nolan that I think was a little unfortunate to be given offside.
"But the first half, we tried the best we possibly could to put more and more pressure on Man City. Of course we would have to do some severe defending somewhere along the line and that wasn't so much in the first half but certainly was in the second."
Source: PA
Source: PA