Sergio Garcia is what other sports call a 'tweener. At the malleable age of 25, the gifted golfer defies categorization and constantly tempts us with the thought that, with the smallest change in his mercurial makeup or improvement in his streaky game, he might suddenly leap an entire level and join the charismatic Big Five at the top of his sport. Or perhaps he will never quite make that jump and remain a fascinating and always fun, but ultimately frustrating in-between man.

Garcia is already great enough that he can defeat a field as good as any in the world (minus Tiger Woods) on a course as central to golf lore as Congressional Country Club. Yet when he does win such an event, as he did yesterday with a scalding front-nine 30 on the way to a 65 for a two-shot win, Garcia inevitably seems to do it when the title of the event is something like the Booz Allen Classic, but never when it is a major championship or other glamour event. Days such as this one at Congressional are, so far, as good as it gets for Garcia. Yet they always promise so much more.

Though young in age, Garcia is already old in golf. When you've played in seven Masters and nine British Opens, parts of your permanent competitive character may already be forged by success or deformed by failure. Ten long seasons ago, Sergio collapsed in his mother's arms after missing the cut at the British Open. And it's been six seasons since he danced up fairways to finish second at the '99 PGA Championship. Yet he's never been close at a major since.

Does any 25-year-old in sports feel like he has been on our celebrity radar so long, while still flying well below the altitude of lasting accomplishment? That's why days like yesterday at Congressional, and weeks like this coming one at Pinehurst in the U.S. Open, are so vital to the final disposition of the Sergio saga.

When Garcia takes the hot putting tip he received this week from runner-up Adam Scott down to Pinehurst, the Spaniard may quickly anoint himself a Sweet Sixth at the top of his sport. Yet even in his latest victory, the dual nature of his game and his personality were apparent. His charm and talent were again balanced against nerves strung a bit too tight on the final holes and a view of himself that may have gotten ahead of his deeds.

At his most appealing, Garcia is open about his failures, yet still confident about his future. Dressed in shades of white (with Sergio and fashion, anything is possible) Garcia laughed openly yesterday about "the ghost of Wachovia" that he dispelled on these closing holes. Just five weeks ago, he became one of the few players -- you can just count them on one hand -- who ever lost a PGA Tour event after leading by six shots entering the last day. Greg Norman pulled the stunt at the '96 Masters and never was the same thereafter.

At the 17th hole, Garcia escaped disaster "by four feet." His approach shot flew the green and could easily have taken a firm bounce and found the water, leading to bogey or worse.

"I didn't think it would be that close" to trouble, said Garcia. But nobody ever does when leads are blown. Yet that's exactly how leads escape. This week, at Pinehurst, if he's in the same spot, will two more yards of adrenaline betray him? Instead of finding misery, his ball kept its traction and pulled back safely on the green. But Garcia's nerves were fully in play as he reached the next tee.

"I could see the [Wachovia] ghost flying around," Garcia said, describing his feelings as he stood on the treacherous, watery 190-yard 18th hole as Scott, trailing him by just two shots, stood in the 17th fairway hunting a birdie after a 351-yard drive.

Garcia hit what he called a "push, slice, shank 8-iron shot" into rough to the right of the green -- a hideous sight, but a dry ball. "I was feeling it," he admitted. However, while Garcia had the good luck of a soft bounce on his wayward approach to the 17th, Scott had the opposite fate. His 133-yard wedge, smoothly struck but barely off line, skipped hard through a bunker and burrowed its way through the rough into Congressional's famous pond.

What kind of game is this? Garcia struck a slightly worse shot into the 17th and ended up on the green. Scott barely sinned at all but, in effect, handed the trophy to Sergio.

Gracious in victory, Garcia thanked Scott for a vital putting tip earlier in the week that had helped his confidence on the greens -- always the weakest part of his emotional arsenal. Told that he had needed only 24 puts in his 65 and had the fewest putts in the field for the week, Garcia threw his arms in the air in disbelief, mocking himself. "I just couldn't miss," he said. "It was going only one place."

So, how can you not love Sergio? Because, just as you think the Garcia of your hopes will become Sergio in reality, he pulls you back. Perhaps, at the U.S. Open, he'll pout that Tiger Woods gets preferential tee times. Or he'll make himself look ridiculous at the Masters when, back in the pack, he mopes that nobody is watching him play. As others roll their eyes, he'll make it clear that, if he were putting well, his ball-striking would have him in the tournament lead. And if frogs had wings, Sergio.

Again yesterday, he pulled the rug from under himself needlessly. "Will you defend?" Garcia was asked, casually. Meaning, would he be back at the Booz Allen next year? For the last 25 years, every winner has said, "Absolutely" or some comparably appropriate response when handed a check for $900,000 for playing golf. Tour champions defend. It's an unwritten rule in golf, although some Europeans, if they are big enough stars or big enough jerks, blow off the responsibility.

"We'll see," said Garcia. Translated, that falls somewhere between "don't hold your breath" and "in your dreams."

So, once again, we meet Garcia the 'tweener. He's not a big enough star, based on tangible feats, to raise the specter of blowing off a long-established tour stop. Yet it's unfair to assume he's just a spoiled too-famous-too-soon jock either.

Sergio's simply young and in-between. He's still too proud, sensitive and self-centered for his own good, but not so much that, in a few years, he might not be a splendid, mature champion. He's almost a full-blown star, but not quite. Key shots on closing holes flirt with danger even at the Booz Allen. A putting tip is not only welcome but also sometimes downright essential.

Yet, he's so close to that next level, as a person and player. In a week, if he were Open champion, no one would be the least surprised. Or, after seeing Garcia's beaming grin on the 18th green yesterday at Congressional, feel anything less than delight.