Leicester manager Claude Puel blamed his side's poor start at Selhurst Park for their 1-0 defeat at Crystal Palace.
Luka Milivojevic's stunning first-half finish ended up securing Palace all three points as Leicester suffered back-to-back defeats to drop to 11th in the Premier League table.
Puel's side put in a much-improved display after half-time but they were unable to find an equaliser, much to the frustration of the Frenchman.
"Our first half an hour was not enough," he told Sky Sports. "For me, it was a poor first half without the right intensity and the right ingredients.
"After we conceded a great goal but the second half was more interesting but without luck. I think we had three or four chances to score.
"It was a tough game," he added.
"We needed to play with good fighting spirit because it was a fight and we weren't ready in the first half to play this game."
Leicester's best chances fell to substitute Rachid Ghezzal and Jamie Vardy in the second-half.
Demarai Gray and Vardy combined to create a shooting chance for Ghezzal, who fired wide before Vardy saw his effort brilliantly tipped onto the post by Premier League debutant Vicente Guaita, who gathered the rebound.
"He had a fantastic opportunity," Puel said. "We are unlucky in this situation.
"We also had two other great chances with Ghezzal. We tried to play well with the right intensity in the second half but we didn't manage to come back in the game.
"Of course it's a disappointment but it's a disappointment about our first half because we had to come into this game with the right mentality and ready for a fight."
Leicester have now suffered back-to-back defeats to Tottenham and Palace in the Premier League and with a Carabao Cup quarter-final coming up against Manchester City on Tuesday, live on Sky Sports Football, Puel wants to see a response from his side.
"We need points of course," he said. "We know coming here is always difficult but we need three points.
"We want to perform and keep a good ambition in the Premier league. We need to correct this of course."