Haaland has scored a record 51 goals in all competitions in the current campaign but was kept quiet by Real defender Antonio Rudiger in the 1-1 first-leg draw last Tuesday.
"Congratulations to Rudiger. But Erling, we cannot forget, is 22 years old and it was the first time he played in the semi-finals of the Champions League," Guardiola told reporters. He was speaking ahead of Sunday's Premier League game against Everton.
"For the first time to go to the Bernabeu, one of the biggest stages, against a top-class club with good defenders, midfielders and strikers, next time will be a little bit easier.
"If the team is able to play a little bit better in some departments in the way we are thinking for Wednesday, maybe it would be easier for him."
Before the encounter against the LaLiga giants, treble-chasing City will look to go four points clear at the top of the league table when they travel to 17th-placed Everton on Sunday.
"The Premier League title is so important even though I know the Champions League is so special. It's many, many months and many, many tough games, incredible effort; this is the most important thing," Guardiola added.
"At the end, come on. What a privilege. The club takes care of us perfectly. We have to be ready to do it."
