"I think a great deal depended on not scoring at Stamford Bridge," said Ranieri.
"We lost [Pavel] Nedved and so the whole left flank was taken apart. The lads did everything they could in the circumstances and we even got back into it with 10 men, so really there was nothing else I could ask of them."
Giorgio Chiellini's second bookable offence was harsh, but Ranieri stood by the Spanish referee.
"Chiellini clearly got the ball, but those tackles from behind always risk something, so we cannot complain about the referee.
"With this tactical system of the 4-3-3, the midfielders had to protect the defence and immediately serve the strikers. Chelsea also had three and so it was difficult to find the right channel, which Trezeguet and Iaquinta did.
"I have nothing to complain about with my forwards, as they did everything they possibly could. Don't forget Chelsea lost the trophy last season on the final penalty and the change of management was probably crucial, as it changed their mentality. The real regret is not scoring at Stamford Bridge.
"For half an hour we pushed very hard, but you can't keep that tempo up forever. We did well to surprise them early on. Towards the end of the first half we tried to raise the tempo, but they were holding the ball and slowing it down."