Hamilton out-qualified Rosberg for the first time in four races in Canada last week, as his team-mate's run of three consecutive pole positions came to an end.
It was Hamilton's supreme focus on sorting out the braking issues to help him overcome Rosberg that left him appearing to be in a downbeat mood throughout the Montreal weekend.
Wolff suspects that Hamilton has had to do some readjustment to take into account Rosberg's pace, but says Mercedes never had any doubts about the Briton's abilities.
"Probably, or maybe, he was surprised by Nico's pace," explained Wolff. "You guys [the media] have written a lot in the last few weeks, as it was not always clear how Nico's pace was compared to Michael [Schumacher] and his days in Williams.
"Now, he [Rosberg] has proved he is really quick, and this came as a surprise to Lewis. But I don't think it is a real problem.
"We saw him strong in Canada, and he was on track for pole position before he missed the braking point, so I think we will see great races from Lewis. I have no doubt."
Team boss Ross Brawn reckons it is only natural that the form between his two drivers will fluctuate over the season, with neither likely to establish total dominance.
"You will naturally get this yo-yoing of form, when you have two drivers as we have who are very, very competitive and very close," he said.
"One of them gets comfortable with the car at a race, and the other perhaps does not find the balance they want.
"That is enough to make the difference between them."
Wolff has also rubbished suggestions that Hamilton has had difficulty coping with a new-found freedom at Mercedes, compared to his former life at McLaren.
"It is different here to McLaren and we are trying to give him the freedom, but that isn't a reason that he didn't perform up to his expectations. He has performed up to our expectations.
"Nico had had a great run, to justify and show that he is a top guy and a top driver, and it is the best situation for the team. Things will eventually balance out.
"I don't think there is any reason to say that he [Hamilton] has a problem or is struggling. It is still early in the season for him. The team is just beginning for him and Nico has been here for a couple of years."
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