Hamilton on pole in Brazil
Although the Frenchman was able to return to the pits for a new nose and post one final quick lap, it was not enough to lift him out of the bottom seven for the first time this season.
"He (De la Rosa) didn't see me and there was no space to squeeze between him and the wall," said Grosjean. "It's a disaster for tomorrow because we have a very good car."
It means Grosjean will start 18th ahead of Caterham duo Vitaly Petrov and Heikki Kovalainen, both fighting for the one remaining seat with the team after Charles Pic was confirmed yesterday.
On his final outing for Marussia, Pic was out-qualified by team-mate Timo Glock, the duo starting 21st and 22nd ahead of the HRTs on the back row, with Narain Karthikeyan in front of De la Rosa.
Hamilton is now looking to end his McLaren days on a high following the 26th pole position of his career, and his first in Brazil.
"It's been a good weekend so far, and I'm grateful to be able to put the car on the front row," said Hamilton. "To have a one, two with Jenson, that's a fantastic job by the team, I'm grateful for all the opportunities the team have given me, and hopefully we can turn it into a positive. The weather is going to be tricky tomorrow (with rain forecast), so it's going to make it more of a lottery. But we've put ourselves in a good position, we'll work together as a team, and we'll make sure we do absolutely everything to get the top result."
Button hinted it to be a shame his partnership is ending with fellow Briton Hamilton as he said: "I'm very happy to be on the front row because my last couple of qualifyings have been a bit tricky.
"To both be on the front row for Lewis' last grand prix with the team...the team is in great shape, and it's a pity things have to change, but things do change."
Webber, with Vettel right behind him, refused to concede whether he will play any role in helping the 25-year-old German.
The Australian said: "We focus on ourselves and do the cleanest race we can. I'll be focusing on my effort in the cockpit given there will be some tricky conditions."