Spurs were knocked out of the Carabao Cup away at Liverpool in midweek and they were outfought on home soil by Aston Villa as Unai Emery's team claimed a 3-2 win in North London.
Tottenham scored their first league goals of the campaign, via Conor Gallagher and Jan Paul van Hecke, but it was not enough to turn the tie around late on.
De Zerbi remains under pressure and the Italian is unrelenting in what he's demanding from his squad in the coming weeks.
"The game was finished before the normal 90 minutes were up. We played well in the first-half, but didn't score, but we created chances.
"We have to become stronger. The players don't need to play better, they can defend better, but we have to put on the pitch something more than we are.
"There has to be blood and fight. We were too fragile. You have to be first to the ball, and if you're not, it's tough to win a game."