One look at Dacio Campos on court will tell you that, even though this is a national championship, it is amateur tennis. But he'll be around for more than one look.

As he defeated Bill Gallagher, 7-6, 6-4, yesterday in the USTA National Amateur Indoor Championships, Campos was attired in T-shirt, faded shorts and blue running shoes. The Brazilian, 19, used a powerful serve to win.

"I was serving all right today," Campos said, "but I wasn't returning serve well because my strings are loose. If you hit the ball a second late on this court, you hit it out."

Campos, seeded sixth, may have had a hard time adjusting to the hard rubber surface at the Crystal City Racquet and Health Club. He grew up playing on the red clay courts of Sao Paulo.

"On clay courts," he said, "you need good footwork and ground strokes. On hard courts you need a great serve and volley."

Despite his years on clay, Campos, a University of Houston freshman planning on a pro career, has gained his most important victories on hard courts. Campos beat Sammy Giammalva, 6-3, 6-4, in Tyler, Tex., last summer on the pro tour, and defeated Brazil's former No. 1 player, Tomas Koch, last spring.

"That was my best win," Campos said of the match with Koch. "My dad and I used to watch him in the Davis Cup when I was growing up."

Campos has been playing tennis since age 6 and at one time was the second-ranked Brazilian junior. His match here was his first on the USTA amateur circuit.

Among other first-day results, John Zahurak outlasted Alan Chanaday, 2-6, 6-2, 7-5, and Jeremy Semple beat Mike Brady, 6-3, 6-3.

The tournament continues through Sunday. Each day's action begins at 9 a.m. Women's play starts Tuesday. Admission is free.