Nicolo Zaniolo looked to have secured three points for the Rome outfti late in the game, but the strike was ruled out for Tammy Abraham's foul in the build-up.
The goalless draw is yet another stumble in Roma's top four pursuit and the Portuguese tactician feels the club are suffering from the decisions because they are too small.
"If the referee made the right decision, then our sport that many years ago became the sport that people love, then this has changed. This is a different sport. A different sport," Mourinho told DAZN.
"If that is a foul, then this is no longer football, we have to call it something else. We need a different name, because it's a different sport.
"If the referee made a mistake and disallowed the goal, he will be the first to be upset at getting it wrong, while for Roma it is deja vu, as this has already happened many times to us this season.
"There is also a third option, which is that Roma are considered 'small' in the eyes of those who are powerful. I leave it there, as the Mourinho who arrived here seven months ago has a different profile to before."
