Real were beaten 3-1 by English Premier League side Manchester United in an International Champions Cup match in Michigan on Saturday following reverses to Italian Serie A clubs AS Roma and Inter Milan.
"We are not happy with the defeat," Ancelotti told a news conference at the University of Michigan stadium in Ann Arbor.
"But I am sure we are going to play with a different spirit in the European Super Cup," added the Italian, who led Real to the 2014 Champions League title in his debut season.
"These are preparation matches. We didn't do things well but everything will change next week."
There was at least some good news for Real as Portugal forward and World Player of the Year Cristiano Ronaldo, who is recovering from a knee injury, came on with around 20 minutes left to surprise the crowd of 109,318, a record attendance for a soccer match in the United States.
Ancelotti, who had said before the game Ronaldo would be unable to participate, predicted that once Real's top scorer was back to full fitness and new signings James Rodriguez and Toni Kroos had joined up with the squad the team would be ready for the new season.
"We can't be ready at this point because some players only started (training) a week ago and they are not in optimal condition," Ancelotti said.
"It's normal to have a day like today as the team is not used to playing without Cristiano or the other players.
"With the players who are returning the quality of the squad will improve."
Ronaldo will have recovered from his left knee problem in time to feature in the Super Cup against Europa League winners Sevilla, which takes place in Cardiff, Ancelotti added.