Fairfax County Board Vice Chairman Martha V. Pennino, a prominent Northern Virginia supporter of Lt. Gov. Richard J. Davis' campaign for the Democratic nomination for governor, said yesterday she believes Davis' rival, state Attorney General Gerald L. Baliles, has won the party's nomination.

Pennino, a longtime friend of Davis', questioned his move to block Baliles' apparent victory by challenging hundreds of delegates won by Baliles in the party's recent delegate selection caucuses. She said one pending challenge of 46 Baliles delegates in Springfield was "frivolous."

"I was sorry that Davis didn't make it," Pennino said in an interview. "I thought he would make an outstanding governor." She said the lack of understanding of the party's complicated selection process "is causing bitterness" and warned that "nobody is going to come out of this happy."

Pennino made her comments after being asked about an April 18 letter in which she wrote a friend, "It is my feeling at this time that Jerry Baliles has won the nomination and we should go forward . . . and I offer him my full support." Asked whether she stood by that letter, Pennino said "absolutely."

Davis campaign officials did not return telephone calls yesterday.

Pennino's remarks, similar to growing concerns expressed recently by Gov. Charles S. Robb, who is publicly neutral, and some other Davis supporters, come as Davis and Baliles prepare for a crucial meeting Sunday of the party's ruling State Central Committee. The committee has been asked to settle key procedural issues over the delegate challenges.

Baliles claimed victory in early April after he led Davis in the caucus voting and announced the support of enough uncommitted delegates and elected officials to give him more than the 1,803 delegates needed to win at the party's June 7 convention in Richmond.

Davis then challenged about 500 of Baliles' delegates before the party's credentials committee, which is considered pro-Davis. He later withdrew about 200 of those. The Baliles campaign struck back by challenging the authority and fairness of the credentials committee. A week-long effort by Robb failed to negotiate an end to the battle.

At the same time, Thomas Vandever, the Charlottesville party chairman and one of 26 Davis delegates from there, said yesterday that his own review of the challenges shows that Davis cannot win without disqualifying at least 50 Baliles delegates and replacing them with his own.

"I think that would be very harmful," Vandever said. "The bloodshed would be too great." Vandever, who said he still hopes Davis can win, said he preferred that Davis stay in the race by competing for the support of the more than 180 officially uncommitted delegates, even though most of them are now claimed by Baliles.

The Davis challenge to the Springfield balloting alleges the process was marred by one official who used a Baliles sample ballot to explain how to vote. The ballot also did not list the delegates in alphabetical order.

"That's a very weak challenge," said Pennino, who said Davis should pursue only those that involved fraud or blatant procedural errors.

The credentials committee, mired in controversy over its impartiality, agreed to postpone its work until after Sunday's meeting. It already has acted on Davis' challenges to 115 delegates, recommending that nearly 50 of them go to Davis and calling for new caucuses for the others. Both moves technically would give Davis a slight lead over Baliles, but neither man would have enough delegate votes for nomination.

Davis and Baliles will make their first joint appearance since the caucuses today when they speak before a group of Fairfax businessmen and lawyers at Tysons Corner.

The credentials committee actions were ruled invalid by the party's steering committee. At the same time, the Baliles campaign has waged a public relations battle against the credentials committee, pointing out that it hired as counsel a lawyer who gave Davis' campaign $750.

The committee also worked only from Davis campaign documents, Baliles said, and used a Davis campaign staff member, Bonnie Reed, as recording secretary after the state party refused to sanction the meeting.

"At this point," Charlottesville's Vandever said, "I think the Baliles people have already made their point . . . . I don't know that Davis can generate the credentials momentum he had."

Vandever said the Charlottesville delegates have never been torn between supporting either Davis or Baliles. "We're going to vote for Davis at the convention," he said, suggesting that the support would switch to Baliles if he wins the nomination.

"Our candidates in Charlottesville have lost so often we have a 'get on board' mentality," Vandever said.