At age 16, Mario Martinez had two career choices: tennis or soccer. He chose tennis. Actually, he had little choice.

His grandfather and father were both national tennis champions in Bolivia. "My father said to me: 'Be more of a gentleman and play tennis.'

"I cried.

"He wouldn't let me play soccer. Now, I'm grateful."

Bolivia lost a speedy left wing forever and gained a third generation Davis Cupper.

"I was expected to play tennis. When I was little, I used my father's racket around the house," Martinez said, flashing a diamond earring in his left ear and a gold chain around his left wrist.

Martinez, 21, advanced to the semifinals of the $200,000 D.C. National Bank Classic yesterday with a 7-6 (7-4), 3-6, 6-2 victory over Claudio Panatta, a match that took 2 hours 36 minutes.

Martinez's link to his family's past is, he says, just skin deep.

"My father was more stylish, smoother. My game is more strong, you can see that," said Martinez, 5-7 and a muscular 170 pounds.

Although his family pushed him into tennis, it wasn't an arduous process. "There was pressure, yes, but I wanted to make my family proud. I think I did it."

Unfortunately, he seldom sees his parents because for the last year he has lived in Potomac to be near his 16-year-old girlfriend, Stephanie Schmidt, whose father Anton provides the Volvos for the D.C. Classic.

"I love Washington, it's my home now. I have everything here," he said.

Martinez, who was ranked 37th in the world at 19, has since had problems. Early last year he injured a sciatic nerve and couldn't play tennis for six months. It took him a year to "get back to my game," he said.

On top of physical problems, he said he suffered financial setbacks, about which he would not elaborate.

"I wasn't feeling too good about myself. I had too many problems. It wasn't very nice," he said.

But Martinez slowly came back last year, winning a tournament in Palermo, reaching the quarterfinals at South Orange and a WCT event in Houston. Still, his ranking had dipped to 74, the worst since he turned pro at 18.

"It took me time to get back my confidence," he said.

Last week in Boston, suffering from the flu, he dropped his second-round match to Diego Perez. "I had a set point on him. But my ears got blocked up," he said.

Now Martinez, in his sixth tournament in 1983 and ranked No. 63 in the world, has glided into the semifinals, beating Dan Goldie, Ramesh Krishnan, fifth-seeded Mel Purcell and Panatta. He will play Jose-Luis Clerc today.

"I'm ready to play the semis," he said confidently.

A self-proclaimed marathon man on clay, Martinez said he never gets tired during a match. Never?

"Once, in Rome (at the Italian Open) last year. I lost in three sets to (Tomas) Smid," he said shyly. "When I play in the third set I'm always mentally strong and in good physical condition. I can fight until then (the third set)."

After today's seemingly interminable match, Martinez did admit that "his feet hurt a little bit. My body is okay."