Going into the Austria weekend, the 2008 world champion said: "Another situation like that (Montreal) and that gap might start to get too big."
Indeed, the mountain became even steeper after qualifying, where Hamilton secured just a ninth place spot for Sunday's race.
Rosberg, in contrast, is third, behind the shock Williams one-two led by Felipe Massa.
In the silver camp, however, it is the German with the psychological edge at present.
And, sparking comparisons with Hamilton's Monaco anger after a controversial qualifying mistake, in Austria it was Rosberg's turn to furrow his brow.
"I could not put the perfect lap together because of Lewis spinning," he said.
"I had to lift off, so that definitely cost me today."
Unlike Rosberg in Monaco, however, Hamilton certainly did not benefit from the qualifying action in Austria.
But although some think Hamilton's sudden spin under braking looked like a technical problem, the feeling within the silver-clad garage is that the 2008 world champion simply made a mistake.
"I'll have to look at the data to see what happened," Hamilton told Sky.
"I'm ok -- it's a long race tomorrow. We have the best engine so hopefully I will be able to move my way up."
Team boss Toto wolff also suspects a driver error.
"We are just looking at the data," he told Austrian broadcaster ORF. "It looks as if the rear brakes blocked, at precisely the moment when he downshifted.
"Whether it was a driver error or a problem, I don't know exactly yet."