City, who are fourth, head into Sunday's clash knowing a win would lift them above Spurs.
"It is essential we beat Tottenham like it will be essential for us to beat other teams in the future," Sagna told Sky Sports.
"If you want to be the champion you have to beat everyone because it's a strange league this year.
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"Back in the day, whenever you were playing a lower team on paper you could be quiet confident. Nowadays everyone can beat everyone, so we don't have an excuse."
City striker Sergio Aguero enjoys playing Spurs, the explosive Argentine notching up 10 goals in eight games against the North London side.
Aguero said he was not looking to avenge City's humiliating 4-1 defeat by Mauricio Pochettino's men earlier in the season.
"It's not a matter of payback, though it was painful to lose in such a way," Aguero told the club's website (www.mcfc.co.uk).
"There's no personal vendetta against Tottenham. If we want to win the League, we have to win against our biggest contenders. We will do all we can to bounce back."
(Reporting by Shravanth Vijayakumar in Bengaluru, editing by Ed Osmond)
