NEW YORK -- Martina Navratilova won't be the first retired athlete to segue into politics, but she's probably the first to run against her longtime doubles partner.

The post at stake in this curious competition is the presidency of the WTA Tour Players Association, a position held the past three years by Pam Shriver, of Lutherville, Md.

At an election to be held Sunday night, Navratilova, an advocate of challenging the tennis establishment, will attempt to block Shriver's re-election bid. But Navratilova, who is retiring at the close of 1994, could find herself running unchallenged if Shriver is not first re-elected to the WTA Tour board by the players.

Though Shriver's dedication to tour issues is unquestioned, her popularity among her constituency has suffered because of her past policy affiliations with the departed WTA executive director, Gerard Smith.

There are some players, Navratilova among them, who believe that Smith and Shriver alienated the tour's former title sponsor, Kraft, and also encouraged the impending departure of Virginia Slims, the tour's founding sponsor, without having an adequate backup in place. The WTA Tour has no sponsor this year and efforts to recruit a title sponsor willing to provide $5 million to $7 million in 1995 have so far met with no takers.