Ahead of United's season opener against West Ham United on Sunday, Mourinho, who has worked in Portugal, Italy and Spain, believes the PL is the most competitive.
"I would say seven teams to fight for the title and 20 teams to fight for the victory every weekend, every match," he told manutd.com. "This is the Premier League - different to any one of the other leagues, and I worked in three other leagues.
"What does it mean for me to be the Premier League champion? I think it's the objective of every one of the top teams and every one of the top teams' managers."