Zouma told the club's website: "It's a bad day for us.
Everyone was upset after the game, especially with the way things changed from being 3-1 up.
We were playing really well, but then we stopped. They put us under a lot of pressure and we couldn't cope with it, and in the end they managed to get the goals that got them the win.
Credit to them. They had nothing to lose and went for it when they were 3-1 down, and I think their substitutes made a difference. When they made it 3-2 we knew it was going to be hard with their fans, but we just didn't do enough and it's incredibly frustrating."
He added: There are still a lot of games to play this year, in the league and in the UEFA Europa League (where the Hammers are through to the quarter-finals), and we've still got a lot to play for, so we can't dwell on this disappointment.
We have another game to get ready for on Tuesday night, so we need to move on quickly. We'll try and learn from our mistakes today, and though we know Tottenham are a good team, hopefully we can get a result in that match."