New signings Ron-Robert Zieler, Luis Hernandez, Nampalys Mendy and Ahmed Musa featured for Leicester against the Scottish Premiership champions, and Ranieri praised the quartet for settling into the squad quickly.
"I am very happy. We have a very good dressing room, the players who have come in are good, there is a very good harmony and for us that was the first important thing," he said.
"The players came back in good condition. We are getting better. Celtic's fitness is ahead of ours. It was a good challenge.
"We have a long journey to Los Angeles now, but the experience of playing in these fantastic matches is important.
"Our fans were fantastic. So many of them travelled a long way to Glasgow so I say thank you to them."