Unseeded Stacey Martin, 14, of Largo and Orlando Lourenco, 20, of Zimbabwe won championships at the USTA National Amateur Indoor yesterday at Fairfax Racket Club.

Lourenco beat Mike Wolf of Stilwell, Kan., 6-3, 7-6, (7-5), in the men's final and Martin won an all-area women's final by beating Michelle Taylor of Washington-Lee High School in Arlington, 3-6, 7-5, 6-3.

"It was my biggest win ever," said Martin, a ninth-grader at Elizabeth Seton High School in Bladensburg.

She outlasted a field of 32 that included last year's tournament winner and No. 1 seed, Sue Taylor of Gladwynne, Pa.; Isabel Pauley (the Virginia AAA high school singles champion), and top collegiate players.

Martin used lobs and passing shots to counter Taylor's more aggressive play.

"Rarely does someone pass and lob and hit winners like she did," Taylor said. "I didn't think she'd keep doing it over and over . . . she's great for a 14-year-old."

Taylor's net play enabled her to win the first set. But she seemed to tire and become flustered by Martin's consistency.

Martin, whose expressionless court demeanor is an extension of her reserved personality, broke Taylor in the fourth and sixth games of the final set and had her at match point in the seventh before Taylor rallied to take the seventh and eighth games. Martin won the final set, 6-3, when Taylor mis-hit an overhead.

"I may not be more aggressive," Martin said, "but I was more consistent."

In the men's final, Lourenco took a 4-3 lead in the first set, then won by breaking Wolf in the final game.

"Mike's got a big serve," said Lourenco, who is the No. 1 singles player at the University of Tennessee-Chattanooga. "I was returning and passing well and I managed to break him in the first set."

Wolf's big serve-and-volley game became more effective. "In the second set he was coming to the net, getting his first serve in more often," Lourenco said. "That's what made it closer. He's really got a tough serve."

Wolf, who plays for the University of Kansas, held his serve throughout the second set, as did Lourenco, but Lourenco passed well with his backhand, getting numerous winners.