Manchester City boss Manuel Pellegrini was bitterly disappointed after his side suffered yet another defeat in the month of September.
It's the third defeat this month for the Citizens.
And the Chilean has urged his players to improve defensively if they are to bounce back from a very negative period.
"When you lose 4-1 it's easy to blame the refereeing mistakes," Pellegrini is quoted as saying by Sky Sports.
"The clear offside for their equaliser was a matter for the linesman and they scored two clear offside goals.
"One part is about the refereeing decisions but another is about our defensive mistakes. We conceded from two set-pieces. It is about marking and concentration, not leadership.
"I thought we played very well in the first half, making many chances, and Tottenham had only one shot on target before their first goal.
"But once it was 3-1 it was very hard to come back. Afterwards they played very well and we played very bad."