Ten years ago, on the final Sunday of the U.S. Open, the day after she had lost in the semifinals, 18-year-old Martina Navratilova announced she was defecting to the United States from her native Czechoslovakia. At the time, Navratilova was the finest woman tennis player in that country, a sports idol, the flower of her federation, someone very special to an impressionable 13-year-old Czech girl named Hana Mandlikova.

Navratilova's defection was considered traitorous by some and courageous by others, but regardless of the political consequences of the act, in practical terms it left the Czech tennis federation with room at the top. In order to prevent similar defections, the federation liberalized its rules, ultimately allowing its players to keep almost all the prize money they earned and to live in the style and even the country of their choice. It seemed all Czechoslovakia asked in return was that the players represent their homeland in international competition, a deal that seems perfectly equitable, for example, to a player such as Ivan Lendl of the Greenwich, Conn., Lendls.

But even with this liberalization of the rules, there still was the problem of the shadowy void left by Navratilova's defection. Navratilova immediately became a nonperson as far as the Czech government was concerned. For years, her matches weren't televised and her scores weren't reported. It was easier to find a poster of Chris Evert Lloyd in Prague than a poster of Navratilova.

Things are much better now. There is recognition of her progress and her prowess. And although Navratilova has not been back to visit, she is satisfied, as she said last night, that she is "supported by the people there." Still, it is hard to watch Navratilova play Mandlikova in the finals of the U.S. Open -- knowing they were coached by the same woman, knowing their lives are inextricably linked by the slow, red clay of Prague -- and not consider the possible political implications of such a match as well as the practical ones.

That the women played a stirring, memorable match was evident. At its beginning, it was as furious and as beauteous in its way as Hagler-Hearns. At its end, it was as thrilling and as uplifting as McEnroe-Borg. By winning, Mandlikova became the first woman since Tracy Austin in 1981 to beat Evert and Navratilova in succession, and pleaded her case for expanding the Big Two into the Big Three. Evert and Navratilova both played their matches waiting and fully expecting Mandlikova to do what she'd done so often in the past: self-destruct. But she didn't, and as Navratilova said after the match, "I said that if she beat me I'd have to give all credit to her, and I'm giving it."

Navratilova always is upset when she loses; she never has been able to treat defeat as an impostor, to shoo it away. But she allowed that this defeat was one of her most devastating ever. Why? Because it was the Open, her national championship now? Because it was Mandlikova, who'd suceeded her in Prague, the loyal citizen, one who'd stayed home and filled the void? Navratilova was miffed at the crowd, which obviously had rooted for the underdog. "Rooting for a non-American," was how she put it before shaking her head in bewilderment. "I'm not saying I'm that much more American than Hana, but only in America can that happen."

Treading lightly on the long, cold issue of defection, someone asked Navratilova if she thought there'd be a celebration in Prague because of Mandlikova's win, and Navratilova laughed jauntily and said, "I'm sure I won't be there, so I don't know." But for her part, she didn't think there was any personal political significance in Mandlikova beating her. "Out on the circuit, it all sort of gets meshed together. The country you come from doesn't matter," she said. "You're all out there in the world."

But Mandlikova seemed to have a slightly different perspective. When asked if she felt she was out of Navratilova's shadow now, considering that they were both Czechs. She smiled and said cleverly, "Martina is not Czechoslovakian, she is American. So I cannot be in any of her shade."

But when she, too, was asked if there might be a celebration in the streets of Prague because of her victory -- the question containing the implicit juxtaposition of her and the expatriate Navratilova -- she quickly said, "I certainly hope so." Pausing for a second, she leaned forward in her chair and said, "I like you ask me that question," then, unsolicited, continued, and in so doing seemed to acknowledge the conflicting positions held by her and Navratilova: "I love my country. I never said anything wrong about my country. I wish they could see what I did, and know that I did it for them."

There is nothing to suggest that Mandlikova and Navratilova dislike each other. To the contrary, there is every reason to believe they are friendly rivals, with the highest respect for each other's game and each other's courage. But it's funny, isn't it, how things work out, funny how no matter where we go we always carry a little part of where we were on the ride.