Washington Post executive editor Benjamin C. Bradlee and Mobil Oil Corp. president William P. Tavoulareas squared off against each other yesterday in a battle of claims and counterclaims about the accuracy of two 1979 articles about Tavoulareas' business dealings that he claims are libelous.

It was Bradlee's turn first and for nearly two hours he described for a federal court jury how the newspaper handled the stories. His overall assessment about the stories was simple: "I think it's a textbook case of how a responsible newspaper should act."

Tavoulareas, testifying for the second time at the trial of his $50-million libel claim against the newspaper, took the stand as a final rebuttal witness and accused the newspaper of twisting the facts in the case to suit its own conclusions.

"They said I was a criminal," Tavoulareas said emphatically. "They said I had broken SEC (Securities and Exchange Commission) rules. I didn't abscond with Mobil funds. I didn't violate SEC laws."

The testimony of two of the top executives at their respective organizations provided a high-powered finish to 16 days of testimony that often had drifted into the minutiae of international oil shipping procedures and the daily routine of life in the newsroom at The Post.

U.S. District Judge Oliver Gasch scheduled final arguments in the case for Tuesday, after lawyers in the case spend Monday arguing over what legal instructions should be given to the jury.

The case centers on articles the newspaper published on Nov. 30 and Dec. 1, 1979. The first story detailed how the elder Tavoulareas "set up his son" Peter in a London-based shipping management firm, Atlas Maritime Co., that then did "millions of dollars in business operating Mobil-owned ships under exclusive, no-bid contracts." The second story quoted a letter written by Rep. John D. Dingell (D-Mich.) to the SEC alleging that the Mobil president may have given "false and misleading" statements to federal investigators in 1977 who questioned him about his business dealings with his son and also may have "misused corporate assets."

When the newspaper refused to retract the stories after they were published, both Tavoulareases sued the newspaper. In a separate $20-million claim, they sued one of The Post's initial sources, Dr. Philip Piro, a Baltimore eye surgeon who was once married to the Mobil executive's daughter Patrice.

Testimony at the trial has shown that Tavoulareas was aware of many of the details of his son's company, which managed the operations of a shipping firm, Saudi Maritime Co. (Samarco), in which Mobil was a partner. But both Tavoulareases have denied they urged George Comnas, Atlas' initial managing director, to take Peter in as a partner.

Bradlee testified that while he is responsible for what appears in The Post each day, he had almost no role in the two stories before they were published. He said he met with Tavoulareas a few days after the stories were published and quoted the Mobil official as saying at one point, " 'Haven't you ever done anything for your kids?' I said, 'Yeah.' "

Bradlee said that as a result of documents Tavoulareas gave him, the newspaper published an article on Dec. 7, 1979 noting that Atlas had repaid Mobil $84,300 that the oil company had originally given to Comnas in consulting fees and expense money when he resigned from Atlas in 1975. The Dec. 1 story, quoting Dingell's letter, had said Tavoulareas "had bought out Comnas' interest in Atlas" with the Mobil consulting fees.

But Bradlee denied that the Dec. 7 story was a retraction, saying it was instead "a classic example of where the truth emerges" as more information becomes available.

The elder Tavoulareas contended that despite the knowledge he had of his son's business he did not make any decisions regarding Mobil's involvement with Atlas, as he had pledged to Mobil officials in August 1974.

"I live every day by Mobil's rules," he declared.