The Hammers' first win in eight games, secured by a second-half goal from Brazilian striker Ilan, edged them four points above the relegation zone.
"We are very happy for today. It was such a tough game for us. I am pleased because the players gave everything," said Zola.
"I am absolutely delighted for the boys because I know what they have been through all this time.
"The result we got last week (2-2 draw at Everton) gave everybody a big boost. This is much better but it is still too early to celebrate. We are not there yet."
One more win would move West Ham on to 34 points and Zola believes that could be enough to secure top-flight survival - but he will not count on it.
"We will stay on our toes."