Inter went 2-0 ahead through Hernanes and Rodrigo Palacio only to be pegged back in the second-half.
"It's shameful to throw away points like that," Mazzarri blasted. "We made the goals all by ourselves.
"We were completely in control of the game, it's inexplicable what happened with Guarin.
"Having given three performances like we have in our last three games, it's hard to accept we have only taken two points.
"I was angry when it was 2-0 because we should have closed out the match. It was like playing Playstation the way we couldn't score!
"I try to help the players avoid these errors, I dedicate time to speaking to them but maybe even 24 hours aren't enough!
"Some of them manage to understand, some of them have limited attention!
"That's the difference between champions and those who are still yet to become champions.
"There are things we need to assess at the club."