Chelsea have been tipped by many as the team to beat in England's top flight this season and 13 points from their opening five matches has certainly helped back those assertions up.
However, the Stamford Bridge side could have made it five wins from five had they held on to a 1-0 lead at title rivals Manchester City on Sunday, Chelsea legend Frank Lampard coming back to haunt his old team when he cancelled out Andre Schurrle's effort in the 85th minute.
Defending champions City were forced to play with 10 men for the last half-hour when Pablo Zabaleta was sent off for a second bookable offence, but a draw ensured Manuel Pellegrini's men did not fall eight points behind Chelsea at this early stage.
Chelsea boss Mourinho felt his team were in control of the situation until Lampard's intervention and believes the team must temper their emotions.
"Against 10 men, we'd won the game. I think when the game gets emotional, it doesn't matter that it's 10 versus 11 - the numbers are not important," Mourinho told reporters.
"When the game is tactical, yes, they do. And when the game was tactical we felt even before the red card, because we sent on Schurrle to win the game, that we were doing it right.
"Against 10 we tried, we scored, we hit the post and had the game apparently under control. But then they scored and the last five minutes the game was emotional and they were psychologically stronger than us, when the crowd got behind them.
"The Premier League, at this moment, is not just different, I think it's crazy.
"We had the 6-3 at Everton, United were winning 3-1 and then lost 5-3 at Leicester, Palace went to Everton and won. More than special, I think the Premier League has become a bit crazy."
