Front and Center Court : Tennis: Natasha Pospich of Calabasas High moves ever forward on the march that is her career.

Natasha Pospich is a good student. Perhaps too good.

Her coach, Dexter MacBride, instructed her to charge the net at every opportunity. Backpedaling was outlawed.

Not one to disobey her coach and uncowed by any foe, Pospich practiced the technique while teaming with MacBride during a recent mixed doubles tournament.

At one point, Pospich lofted a shallow lob to her male opponent and, instead of sidestepping the ensuing smash, darted forward. The ball, now a screaming yellow flash, plunked her between the eyes. The shot was so forceful that Pospich’s ever-present plastic visor cracked in two.

Dazed but uninjured, Pospich turned to a horrified MacBride and frowned.

“Well,” she said, “you told me not to back up.”

MacBride was amazed she was still standing.

“It’s a combination of spirit and attitude,” MacBride explained. “She doesn’t want to be upstaged.”

Pospich, 17, is as likely to move backward as is a Rolex watch. She is determined to plod forward with her tennis career, plowing through opponents along the way.

The Woodland Hills teen-ager will move on to the Southern California Junior sectional championships, the main draw of which begins Wednesday and includes 1,888 juniors from San Luis Obispo to San Diego. Pospich, ranked fourth in Southern California in the girls’ 18-and-under division, is seeded third in the tournament.

A senior-to-be at Calabasas High, Pospich already has won a national doubles title on the clay courts in Virginia Beach, Va., with Nicole London of Rancho Palos Verdes. With Stacie Jellen, a freshman at Calabasas, Pospich won the 1989 Southern Section girls’ doubles championship.

Despite nursing a sore ankle, Pospich defeated La Jolla’s Ditta Huber, 6-1, 6-4, to win the 18s division singles title of the Ojai Valley tournament this year.

Two weeks ago, Pospich played on the 10-member Southern California team that defeated a team of juniors from Northern California to win the Maze Cup.

Pat Puccinelli, an assistant at Pepperdine, has noticed a fire in Pospich.

“She’s in that new breed,” Puccinelli said. “Along the Steffi Graf-type of existence. She’s real strong and really is forcing. She forces her own destiny.”

Pospich, who often yells after hitting a winner, says she is calm on the court despite her outwardly aggressive demeanor.

“I wouldn’t say I’m really laid back,” she said. “I’m pretty intense, but I don’t put drastic pressure on myself. I play better when I’m not under all that stress.”

A long athletic career has made Pospich adept at defusing the pressure of competition. “I love playing on center court,” she said. “I just love playing in front of people.”

Before tennis, she competed for the West Valley Eagles, a junior track club. She set the state’s top marks for 10-year-old girls in the high jump and shotput; her 440-meter relay team finished second in the state.

MacBride reasons that Pospich’s sheer athleticism weighs against her on occasion; she relies on her physical abilities and strays from the fundamentals.

“She uses her ability to run a little too much,” MacBride said. “I’m trying to enhance her shot-making ability. If you’re smart and somewhat talented, that’s better than being completely talented with no schooling. I’m trying to make her think while she plays.”