Roberto Mancini felt Manchester City learnt "an important lesson" from their 2-2 draw at Leicester in the third round of the FA Cup.
Mancini believes the excellent performance of the Foxes spelt out the need for his players to be at their best against non-Premier League sides to achieve their dream of reaching the final.
A second-half blunder from Eastlands keeper Joe Hart gifted Andy King the equaliser, but Mancini's side looked vulnerable all evening against set-pieces after Leicester newcomer Sol Bamba scored inside 50 seconds.
Mancini said: "For us, it is an important lesson, that if we want to win the FA Cup we must always play at 100% because every game is difficult.
"We conceded a goal after one minute which was very strange. I think we slept for two or three minutes.
"They caused a lot of problems from set-pieces and Bamba is good in the air, very tall, and a big problem.
"We will have to work on that for the replay. When we play at Eastlands, we must pay attention.
"I think we played 100% but maybe sometimes, when you play a team in the Championship or the third division (League One), you think 'that is easy'.
"In the FA Cup there is never an easy game. We want to go to the final.
"It is important when we play other teams, we must focus on the game like when we play in the Premier League.
"But it is important we have another chance."
New £27million striker Edin Dzeko looked on from the stands and will make his debut against Wolves next weekend.
Mancini said: "He will be an important player for us. He is different from the other strikers we have.
"He is one more choice for me.
"He will be very important for the rest of the season, important in the next match.
"He will be available for Wolves in the next game."
Leicester midfielder Richie Wellens ended the game with his hand bandaged up after he tangled with Nigel de Jong.
But Wellens believes De Jong's actions were of an accidental nature.
Wellens said: "It was just a little stamp on my hand (by De Jong). I don't think it was deliberate.
"I hope it wasn't but you've just got to take the bumps with the bruises.
"I just felt his studs go into my hand. I don't think he meant it. You will have to ask him that but I'd like to think it was just an accident.
"He didn't say anything to me. Just a little smile! He caught me right on the knuckle so it was painful.
"He is a physical player and if I get the chance to be physical with him, then I will be.
"These things happen. I'm not accusing him of anything."
After Sol Bamba's instant impact on his debut, the visitors seized control with James Milner - with his first goal for the club - and skipper Carlos Tevez netting before half-time.
But Leicester rallied and Hart failed to collect one of many dangerous crosses from Paul Gallagher - and King did the rest for his 10th goal of the campaign.