William Gallas has insisted that Tottenham Hotspur must get a "good result" in next weekend's North London derby at Arsenal.

Spurs slipped down to seventh place in the Premier League table on Sunday following their 2-1 defeat at Manchester City.

Gallas now believes that his side must avoid defeat against their local rivals to keep their ambitions of a top-four finish alive.

"It will be a big derby," said the Frenchman. "We have to get a good result there. It won't be easy but we have to do something."

Gallas joined Tottenham from Arsenal in summer 2010.