The Frenchman was also a fault for Hull's penalty just after the half-hour mark, but his coach put both incidents down to bad luck.
"[Mangala] was very unlucky with the own goal and after that he arrived late for penalty but we continue to trust him because he is a very good player who had very bad luck," BBC Sport quotes Pelegrini as saying.
"During the week when we scored seven I felt that the team was tired. I think today we played a very good team. They defended very well and we scored four goals which was very good. It was very important to win three points here because we cannot allow to drop any more points on Chelsea."
The win moves City up to third place in the Premier League table.