It was the worst public tongue-lashing of his life, and Joseph P. Yeldell had to sit there and take it.

Although his jaw thrust out in his familiar gesture of defiant pride, his eyes glanced nervously around the crowded courtroom Monday as a federal prosecutor attacked what the one-time IBM sales executive and influential city government official has always said he valued most - his good name.

The man who had boasted that his middle initial - "P" - stood for "powerful," heard himself described as a corrupt official, the recipient of a bribe, and a liar. At one point the prosecutor, talking about Yeldell's ethics in government, laughed sarcastically.

For reclusive millionaire Dominic F. Antonelli Jr., the experience was perhaps even more humiliating, intruding deeply into the personal and business privacy he had gone to great lengths to protect over the years. Once, when he missed the departure of a cruise ship, he had taken a taxi overland to the next port rather than call attention to himself by riding a special launch to the ship.

Now, he could not stop attention of the most painful king from being focused on himself, whom prosecutors delighted in calling "the $20 million man" during the three-week-long trial. On the witness stand, Antonelli was forced to disclose the most intimate details of his great wealth. When a prosecutor stood right next to him while emphasizing a point during his closing argument, Antonelli's face reddened.

The shame of this trial was not the only thing these two seemingly improbable friends and codefendants had in common. Both had risen from poverty to power - Yeldell, 46, in government as the administrator of the city's welfare department and a top assistant to Mayor Walter E. Washington and Antonelli, 56, in business to the top of a self-built empire of parking lots, real estate developments, financial institutions and other holdings.

Yeldell was born in Washington and became a champion orator at Cardozo High School. Antonelli came here from Oklahoma as a young boy, dropped out of McKinley High School to go to work and lived in one of the dilapidated rowhouses that then lined short, narrow DeSales Street NW in downtown.

Antonelli, shy in social settings, way from all account a tiger in the business world. He quickly expanded a small parking lot on DeSales Street to his first really big parking lease deal when, in 1974, he won control of the huge Great Plaza lot behind the District Building at 14th Street and Pensylvania Avenue NW.

As principal owner of Parking management Ing. (PMI), the city's largest parking operation, he still operates that lot today, along with more than 100 other parking lots and garages. He also owns, with partners, more than $100 million worth of real estate in the Washington area alone.

While Antonelli was accumulating the financial power his codefendant would one day covet, Joe Yeldell was in college, winning friends with his gregarious manner and becoming what his school pals remembered as a Big Man on Campus.

Yeldell attended D.C. Teachers College, dropped out in 1954 to join the Air Force, then finished his education at the University of Pittsburgh, receiving a master's degree in mathematics. Returning to Washington and a teaching job in 1961, Yeldell began a long climb to local prominence.

He joined IBM as a sales trainee in Washington and before long was promoted to marketing representative and assigned to one of the corporation's most prestigious accounts - the White House.

From the contacts he developed there, Yeldell boldly and successfully offered himself as a candidate when then president Lyndon B. Johnson was appointing members of the first D.C. city Council. A newspaper article Yeldell used to promote himself for the job had caught Johnson's eye.

Still unknown in many parts of the city, council member Yeldell slowly began to build political bridges. When he lost a 1971 bid to become the city's nonvoting delegate in Congress, Mayor Washington offered him the chance to run the newly created D.C. Department of Human Resources.

His five year in that job were marked by tories of administrative mismanagement of the sprawling, perhaps unmanageable agency, and Yeldell's penchant for the perquisites of power. The DHR diretor's handsomely decorated office was second only to the mayor's in size and comfort, and Yeldell himself bristled when Congress refused to include money in the city budget for his personal chauffeur.

At one point in the late 1960s or early 1970s, Yeldell and Antonelli began encountering each other at various social and civic functions. By now Antonelli was a prominent member of the city's business community. Some of his business associates were also close to Yeldell' political benefactor, Mayor Washington.

Yeldell's public prominence, however was not matched by a strong financial positions. A travel agency he had opened with several friends and DHR associates had become a drain on his $47,500 city salary. He badly needed a loan. And before long, he got it with Antonelli personally guaranteeing the loan.

Yeldell's wife, Gladys, also worked with the two incomes the family bought a rambling split-level house in Washington's fashionable Platinum Coast off upper 16th Street NW. But their home was modest in comparison to the 10-acre Potomac estate - with a large pool, riding stable and tennis court - occupied by Antonelli.

By now Nick Antonelli was a director and stockholder of Madison National Bank, which he had helped to found. He was also busy buying and developing property all over the city. Yeldell was busy trying to manage the huge welfare agency and his troubled personal business affairs. In 1973, they began to deal more with each other.

In addition to Antonelli's help with Yeldell's travel agency loan, Yeldell's actions as DHR director began to overlap with Antonelli's real estate dealings. Yeldell repeatedly acted to clear the way for construction of downtown hospital - a replacement for Doctors Hospital - in which Antonelli had a financial interest.

In 1976, as comlaints about management problems in DHR continued to mount. The Washington Star published charges that Yeldell was putting friends and relatives on his city payroll. Yeldell was eventually cleared of any legal wrongdoing by city investigators, but the controversy loosened tongues and led to more stories.

The revelation that produced serious legal trouble came in a Nov. 19 front page Washington Post report that Yeldell had ignored objections of other city officials in approviding a $5.6 million city lease of a building Antonelli owned at 60 Florida Ave NE. as a DHR service center. After The Post later revealed that Yeldell had received a $33,000 loan that had appeared to come from Antonelli about the same time, federal prosecutors began the bribery investigation that led to yesterday's convictions.

Mayor Washington, slow to move against his friend and political confidant, first transferred Yeldell from his DHR post to a top job as the mayor's general assistant. Only after Yeldell had been indicated did the mayor decide to place him on administrative leave.

Yeldell, and the mayor's handling of him, became an unspoken issue in Walter Washington's unsuccessful attempt in September to win renomination. He had to run without Yeldell's acknowledged campaign expertise and against what a Washington Post poll showed to be unfavorable reactions to the Yeldell affair among a large segment of city Democrats.

Antonelli steadfastly refused to discuss either the news stories or the federal investigation. Yeldell, on the other hand, hotly protested his innocence of any wrongdoing.

In his only public accounting of the leasing argument prior to his trial, Yeldell told a Washington Post reporter in an April 1977 interview that he and Antonei had not mixed Yeldell's personal financial problems with any actions he took as DHR director.

"This is what disturbs me about these news reports," said Yeldell, who then acknowleged for the first time that he had sought Antonelli's help in arranging the two personal loans to cover his travel business and other debts.

"I don't ever get into negotiations in this (DHR) department . . . I never negotiated Antonelli's lease or anybody else's lease. It's all done outside this office," said Yeldell, who insisted then that he did not know the source of the second $33,000 loan he obtained in May 1976 shortly after DHR leased the Antonelli-owned building.

Ironicall, it was characteristic DHR inefficiency involving that lease that ultimately brought Yeldell's and Antonelli's mutual said to light.

The first hints that perhaps there was something unusual or even unorthodox about the 60 Florida Ave. NE lease came six months after the contrict was signed and then only because the building itself was sitting empty while the city continued to pay $22,063 in rent for it each month. What started as another story of DHR mismanagement turned into a major city government corruption scandal.

In the end, Yeldell's loud protestations of innocence to the press, to city investigators and to the jury came back to haunt him during the trial when prosecutors showed them to be lies.