George Osborne ridiculed the pre-Budget report as "tractor production figures from the old Soviet Union", accusing the Chancellor of single-handedly destroying the public finances.
The shadow Chancellor won howls of laughter from the Tory benches as he mocked Mr Brown's steamroller style in a pugnacious performance that raised the morale of his party.
Speaking just 24 hours before his close friend David Cameron is expected to gain the party leadership, Mr Osborne launched a personal attack on Mr Brown.
He said: "This is a tragic story of a Chancellor who has had to wait so long to go to Number 10 that his reputation at Number 11 is crumbling."
But he faced a bruising return salvo from the Chancellor, who was twice rebuked by the Speaker for turning his fire on Conservative policy.
Mr Brown quoted Mr Osborne's claim at the weekend that he had been "brutal" in his dealing with his Tory counterpart.
He said: "I have to say I am afraid, having heard your speeches, I have not been brutal enough.
"They say the Conservatives are about to skip one generation. Perhaps it is time they skipped another one as well."
Tory MPs cheered as Mr Osborne attacked Mr Brown for being forced to downgrade his growth forecasts, warning: "No wonder he looks so gloomy. The longer he stays at the Treasury the more his chickens come home to roost."
He said: "The real story from today's report is that his deficit has gone up to £10bn. He's borrowing £151bn over the next five years, £17bn more than he predicted and he has just announced that growth in this year is half what he predicted before the general election. His forecast for next year is lower too.
"His golden rule is now tarnished and discredited, productivity growth has slumped, business investment has collapsed and this year Britain has some of the weakest economic growth in the developed world."
He lambasted Mr Brown for trying to "sabotage" Lord Turner's proposed pension reforms. "The man who created this pensions crisis is the very same man who is now standing in the way of providing a solution ... This country needs a Chancellor who is interested in reforming Britain for the future, not in defending your failed policy of the past.
"This is a Chancellor forced into the humiliation of admitting he got it all wrong. This is a Chancellor who is past his sell-by date. This is a Chancellor who is holding Britain back."
Leading Conservatives praised Mr Osborne's performance after he delivered the most important set-piece since he was propelled to his shadow Treasury role.
Alan Duncan, the shadow Transport Secretary, said: "It was a good day for George Osborne and a bad day for Gordon Brown - Brown isn't used to a noisy House and he must realise that a litany of anti-Tory gibes doesn't work. George Osborne cut through him. The mood around the Commons has changed."
Oliver Letwin, the shadow Environment Secretary, said: "I thought that the Chancellor was on the back foot and that George kept him firmly there."
A Cameron ally said: "Labour had a muttering and disruption campaign against George Osborne, but he sailed through. He got the most important messages across and Gordon Brown didn't even attempt to answer his crucial questions."
But other MPs were unconvinced. One Labour MP said: "It was a useless speech - it just didn't work. He looked pale - Gordon won't have any trouble seeing him off."
A senior Liberal Democrat said: "I don't think George Osborne will cut it - I can't see him lasting in that job. The combination of him and David Cameron is like something from Brideshead Revisited."
Vincent Cable, the Liberal Democrat Treasury spokesman, said Britain was being outperformed by Sweden and Spain while oil importing countries were booming.
He said: "What the Chancellor has demonstrated is his talent for producing rabbits from hats while disregarding the really big long-term challenges."
He asked the Chancellor: "Why can you also not say: 'I have made mistakes, we've exaggerated the projections, there has been administrative over-centralisation'? Why can you simply not stand up and acknowledge your own failures?"
Kenneth Clarke, the former Conservative chancellor, said: "The people who still believe in the fiscal rules as in his description of the public finances also probably believe in fairies."
Andrew Smith, the former work and pensions secretary, applauded measures on housing. He said: "Building more homes can both raise economic growth and tackle acute housing need.
"Isn't that just the combination of social justice and economic opportunity that will be welcomed."
But Stewart Hosie, SNP MP for Dundee East, attacked Mr Brown's decision to raise taxes on North Sea Oil producers, saying the regime could lead to "rapid and irreversible loss" of resources, skilled workers and equipment.
The former Labour deputy chief whip George Mudie said: "Facing as we are one of the worst winters for many years I would like to congratulate the Chancellor on the £300m for pensioners for central heating."Reuse content