79th CALIFORNIA AMATEUR CHAMPIONSHIP : Wi Casts Tension, Local Contingent Aside at Pebble : Golf: Thousand Oaks teen beats Van Nuys’ Steinberg in quarterfinals, Oxnard’s Stankowski in sudden-death playoff to advance to final.

As the ocean pounded out a steady beat against the rocky and majestic shoreline of the famed 18th hole at the Pebble Beach Golf Links, a sea lion poked his head high above the undulating kelp.

A mouthful of fish could wait. Even this slick-skinned swimming mammal, it seemed, wanted a glimpse of young Charlie Wi, the wonder from Thousand Oaks who is now just a step away from completing a rather astonishing feat.

Wi, 18, who graduated from Westlake High just two weeks ago, swept into the final of the 79th California Amateur golf championship Thursday, ousting veteran Craig Steinberg of Van Nuys in the quarterfinals and then overcoming some superb play from Paul Stankowski of Oxnard in the semifinals, knocking down a three-foot birdie putt on the first hole of a sudden-death playoff to earn a berth in the championship round.

Wi will take on 39-year-old Gary Vanier of Oakland in today’s 36-hole match-play championship and could join just a handful of teen-age winners of the prestigious event, including PGA Tour players John Cook and Bobby Clampett.

Might Wi be intimidated by the brusque, grind-it-out nature of Vanier, who has played golf for more years than Wi has breathed?

“No way,” said Wi. “I’ll be here to play golf. If he wants to talk and try to intimidate me, let him. I can be a jerk too if I want to be.”

Beneath the tough front, however, is a young man who at times during his remarkable weeklong run on the Monterey Peninsula has been an absolute wreck.

“On the playoff hole I was so nervous I couldn’t stand it,” Wi said. “I stood over that birdie putt to beat Paul and my hands were sweaty and all sticky. God, was I nervous.”

He had every right to be. It wasn’t until last week that Wi learned he would be playing in the tournament, having missed qualifying by a stroke in May. But as the first alternate, he was summoned just six days before the event began when another player withdrew.

Wi didn’t start the tournament like a player who planned to be around very long. He struggled to a 75 at Cypress Point.

“I was so nervous that day I didn’t even want to get out of the car,” Wi said. “When I did, I forgot my sweater and spent the rest of the day freezing in the wind. Then I had a terrible first hole and I said to myself, ‘This is going to be a very long , short tournament for me.’ ”

He came back on Tuesday, however, with a sizzling round of 68 at Monterey Peninsula Country Club, the second-lowest score of the two-day stroke-play portion of the tournament, and entered match play as the No. 3 qualifier behind Stankowski and Mark Johnson of Barstow.

On Wednesday, he cranked out match-play wins over Mitch Harrison of Campo and Randy Bridge of Hollister.

And on Thursday, he took on Steinberg, a 32-year-old optometrist who had advanced to the quarterfinals for the third consecutive year and figured to make short work of Wi.

It was not to be. Wi rolled over Steinberg, 3 and 1, and then teed it up against another Valley-area player, Stankowski, who will be a senior at Texas El Paso in the fall and is the defending Southern California amateur champion.

Stankowski, 20, jumped to an early lead when he parred the second hole at Pebble Beach and Wi stumbled to a bogey. But Wi evened the match on the par-3 fifth when he rolled in a tricky, downhill four-footer for par.

On the par-5, 516-yard sixth hole, Stankowski crushed a drive 330 yards, sailing his tee shot more than 50 yards past Wi’s. But Wi put the pressure on Stankowski at the green, sinking a 45-foot birdie putt that broke twice during its long roll. Stankowski, however, responded with his own birdie putt from eight feet to prevent Wi from winning the hole.

“You know what?” Wi said. “I pushed that putt. I really hit it bad. I can’t believe it went in.”

On the seventh hole, Wi sank a seven-foot birdie putt to take a 1-up lead, and he opened a two-hole lead in sensational style by winning the 10th hole.

Wi’s drive on the long par-4 went right and over a cliff. He took the penalty and dropped a new ball and proceeded to slam a seven-iron from 170 yards that nearly went into the cup. The ball hit the green and rolled directly at the pin, stopping just two feet shy. He made the putt for a par and a stunned Stankowski then missed an eight-foot putt for his par.

“I was just shocked,” Stankowski said. “But Charlie is a great player, and great players make shots like that.”

Stankowski moved to within one hole of Wi with a par on the 13th hole and evened the match on No. 14 when he dropped a two-foot putt for par and Wi bogeyed.

The two stayed deadlocked to the 18th green, where Wi had a chance to win with a 10-foot putt for birdie. But the putt moved left and stopped three inches from the cup, forcing a playoff beginning at the first hole.

“I knew I had to end it on the first hole,” Wi said. “Paul can reach the second hole in two shots and I can’t. I bogeyed the second hole the last three times I played it.”

End it quickly he did. Hitting his second shot from 130 yards in the middle of the fairway, Wi drilled an 8-iron dead at the pin. The ball stopped three feet away, and Wi moved into the final by dropping the putt for a birdie.

“I sure kept it close, didn’t I?” Stankowski said. “I did all I could do, but then Charlie took over on the playoff hole. My hat is off to Charlie.

“When I got off to a good start and went 1-up on the second hole, I knew that didn’t mean much. I knew this thing was going to go 18 holes. I was wrong. It went 19. I can accept the loss a little easier because it was Charlie and I know how good he is.”

Wi, who will head to Nevada Reno on a golf scholarship in the fall, said he plans to bring the championship trophy home tonight. He just hopes he remembers what happens.

“After I got behind early today I just looked at Paul and said, ‘Wow.’ That’s all I could do. Just ‘Wow.’ How did I ever come back to beat him? I was so nervous I can’t remember anything.”