The 28-year-old German, who lies three points behind Hamilton in the drivers' championship, knew that his error had not only ruined his own lap, but probably wrecked Hamilton's prospects of outpacing him.
Race officials announced they were investigating the controversial incident.
As many observers suggested his mistake may have been deliberate and could spark a serious deterioration in the relationship between them, Rosberg batted away questions at the post-session news conference.
Asked for a response to Rosberg's apology Hamilton shrugged: "I don't have an answer to it."
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Rosberg continued: "No, it wasn't the ideal way to end qualifying... I thought it was over. I thought the track would ramp up and someone else could beat my time.
"So, of course, I'm happy it worked out. Pole at home is fantastic. It couldn't be better...."
A visibly upset Hamilton found it difficult to smile for the photographers or speak to reporters as he reflected on another failed effort to secure his maiden pole position in the Mediterranean principality.
Australian Daniel Ricciardo, who qualified an impressive third for Red Bull ahead of his team-mate four-time champion Sebastian Vettel, summed up the mood.
- Rosberg lost control -
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"I think all three of us don't seem to be too pleased with ourselves... I think we all feel that we've left something on the table. I fought the car all the way round in qualifying.