As the day darkened last Monday, and frenzy was rampant on the floor of every money market in the world, the center of gravity in The Post's newsroom calmly shifted to the northwest corner of the vast editorial bullpen, where financial news is king. It took on the look, as the evening wore on, of a freshly bombed high-rent district. Executive Editor Ben Bradlee and Managing Editor Len Downie, having rousted themselves from posh private sanctums, were now setting up mobile command posts amid the economic debris of desk-to-desk intimacy in the business news section.

It was a scene right out of the movie "The Front Page." The biggest financial story in two generations had caught The Post's business news department during a week of orderly transition; there was a changing of the guard, scheduled months earlier, with Peter Behr taking over command of the huge financial news operation from veteran Frank Swoboda, who had advised management a year ago he wanted to return to his first love, labor reporting.

From the moment New York markets opened Monday, the routine of the newsroom gave way to accelerated and concentrated activity. The momentum increased by the minute and by the hour. It reached its crescendo peak about 10 p.m., when the roar of 13 gigantic presses took over.

Nobody was heard to say: "This is more fun than Watergate."

A quick look back at the past nine or 10 days would suggest a top-notch performance. There were a few uneven spots, where it might be charitable to say that editors were being overly protective of the reader and the establishment generally, fearing bigger headlines or more prominent play might contribute to panic, or encourage it.

It should be noted here that The New York Times and The Wall Street Journal were right up there with The Post, and the only failing I personally encountered was in the electronic media. When I turned on CBS-TV one morning, a commentator intoned that the U.S. Marines had landed, had established a beachhead and were preparing to move inland. I held my breath until I suddenly realized the commentator was using a metaphor to describe the market situation -- a most unfortunate allusion.

On Thursday, when the market first broke, The Post did lead on the front page with a one-column head. It was hardly a "scare" story. It merged the 95.4-point market drop with a report of a widening trade gap. But the Business section played the story big, and if the reader got to that section, there was an eyeful. Both stories were written by the same reporter, Stuart Auerbach.

On Friday, there were two front-page stories on the economy, one by The Post's elder economic statesman, Hobart Rowen, who couldn't resist writing: "The stock market, ignoring reassurances by Reagan administration officials, fell sharply again yesterday." Both stories were at the bottom of the page. Saturday, The Post reported "the biggest nose dive yet" on Wall Street, but the story played second fiddle to Persian Gulf developments. On Sunday, there was a low-key, one-column, evenhanded story below the fold saying the market was facing a crucial test. Not a story to start a run on the bank. Monday's paper contained no hint of what the day might bring, even though before the final editions went to press, there must have been some signs from daytime markets in the Far East that it was going to be a rough day. The Monday Post suffered from market anemia.

The Post deserves high marks for its performance. It duly reported that Washington Post Co. stock on the American exchange closed Friday at 221, and when trading resumed on Wednesday, it had taken its lumps along with the stock of other companies, dropping 22 points. Amid all the turmoil, Post editors somehow found space to advise readers on Wednesday that The Post Co.'s third-quarter profits were almost triple the earnings for the third quarter a year earlier.

Late Friday afternoon, there was a new surge of excitement in financial news, with Mr. Bradlee and Mr. Downie again in shirt-sleeve command. Swarms of newspeople moved in. Someone trundled in carts of huge cholesterol cakes and gallons of diet soft drinks. It was time to say farewell to Assistant Managing Editor Swoboda.

Things were back to normal.