The loss followed the 4-1 mauling at the hands of Napoli last weekend and speaking to reporters, Zeman said his side should have won a match they controlled for large periods.
"It was a game we should’ve finished off in the first half and apart from Catania’s goal, we basically controlled the second too," he told reporters.
“We were a little chaotic and confused. We were unable to finish off scoring opportunities and Catania punished us. We need more belief and more desire to win.”
The coach singled out Mattia Destro for wasting several good chances, and explained his decision to bench Daniele De Rossi.
“Destro creates several chances, but for now is getting them wrong," he continued.
"As for De Rossi, my choices depend on the individual match. Today I chose [Panagiotis] Tachtsidis to create something more and I think he performed his role fairly well.”
The 65-year-old also said he hoped Francesco Totti, who pulled out of the match during the warm-up, would be fit for Wednesday's Coppa Italia clash with Fiorentina.
"I hope Totti can already be back on Wednesday in the Coppa Italia. We are Roma and we must try to win in every arena.”