NEW YORK (AFP) - A US bankruptcy court Saturday approved the sale of key assets of fallen US investment bank Lehman Brothers to its British competitor Barclays. "The purchase agreement constitutes the highest and best offer for the purchased assets, and will provide a greater recovery for the debtors' estates than would be provided by any other available alternative," US judge James Peck. Under the 1.75-billion-dollar deal, Barclays will acquire Lehman Brothers' investment banking and trading units that employ about 9,000 people in the United States and a skyscraper the bankrupt US firm occupied in Manhattan. The purchase also involve Lehman Brothers branches Canada, Argentina and Uruguay. Lehman Brothers went bankrupt last Monday, plunging the global financial system into turmoil. The massive Lehman bankruptcy filing in US federal court in New York listed 639 billion dollars in assets and 613 billion in debt. The Chapter 11 filing came after Barclays walked away from a merger deal with the beleaguered US investment giant, saying that such a tie-up would not have been in the best interests of Barclays' shareholders. But Barclays announced in a statement Wednesday that it had reached an agreement to acquire Lehman Brothers North American investment banking and capital markets businesses. "This is a once in a lifetime opportunity for Barclays," said the British bank's president, Robert Diamond. "We will now have the best team and most productive culture across the world's major financial markets, backed by the resources of an integrated universal bank." Judge Peck said in his ruling that the sale "must be approved and consummated promptly in order to preserve the viability of the businesses subject to the sale."