A decision by General Motors Co to sell a controlling interest in its European unit, Opel, was the first major decision for GM's new board and an important test of the U.S. government's pledge to let the directors and management run the company.

They had everything they needed and they decided, John Smith, GM's top negotiator in the talks that settled on Canadian parts supplier Magna said of the automaker's board that was brought in after GM's June bankruptcy.

Bristling at suggestions GM dragged its feet over the past several weeks as pressure mounted from the German government to make a decision, Smith said the 13-member board acted as swiftly as possible, considering members were totally new.

Smith said the board has little to no experience overall with the auto business, U.S. or overseas, and sought answers to a number of complex questions as options were considered.

In late August, the board led by former AT&T Inc Chairman and Chief Executive Ed Whitacre declined to endorse the Magna deal, instructing management to explore another sale or consider keeping Opel.

That step was viewed by some analysts as a signal the board would not be a management rubber stamp and illustrative of a more aggressive executive culture at GM -- two characteristics demanded by Obama administration officials who appointed a majority of the new panel.

The U.S. government holds a controlling stake in GM in return for extending the automaker $50 billion in bailout and bankruptcy financing since January.

The administration's autos task force, overseen by the White House and the Treasury Department, facilitated GM's restructuring and signed off on a framework for a Magna deal in May.

At that time, a call by U.S. President Barack Obama to German Chancellor Angela Merkel helped cement the deal that involves no U.S. financial commitment and bars Opel from selling vehicles in the United States.

Senior Obama administration officials said in recent weeks they would not influence final details of the Opel decision even though Merkel's government could receive a boost from the Magna choice ahead of a September 27 election and lobbied for the selection.

We have regular communications with GM on this and many other issues, but this is ultimately up to GM and the U.S. government will not determine the final decision, a Treasury official said earlier on Thursday, declining to comment further.

A congressionally appointed watchdog overseeing management of U.S. corporate bailout funds said this week in a report that overseas political pressure on GM over Opel was the kind of scenario the administration had to resist if its pledge to stay out of management affairs was to be viewed credibly.

Treasury Secretary Timothy Geithner told an oversight hearing on Thursday the administration had indeed avoided intervening in day-to-day management of GM and Chrysler, in which the government holds an 8 percent stake.

Such intervention could seriously undermine the companies' long-term viability and, consequently, their ability to repay the taxpayer for its investment, Geithner said.

(Reporting by John Crawley, Glenn Somverville and David Lawder; Editing by Gary Hill)