Once a lifetime, everything ought to go right.

Gary Koch discovered today that, at least for four fleeting hours, golf could be a game, not a shame. In the dizzy span of an afternoon, the 30-year-old Tour journeyman saw one daydream after another come to life.

A hole in one? Your first ever on tour? After spending the last four years as a rabbit, you deserve a break--a Koch break.

The best round of your life? A seven-under-par 65 on Doral's Blue Monster in which you never make a bogey, save par from grief five times and need only 23 putts? You've got it. After all, a guy who didn't earn a place on this season's all-exempt tour until the last tournament last season has had enough aggravation.

How about leaping from second place into the lead after three rounds of the Doral-Eastern Open? After winning just two obscure tournaments in your career, it's only justice that, for one day, Jack Nicklaus and Tom Kite and Ray Floyd should be left behind.

What about building a four-shot lead over Ed Fiori going into Sunday's final round with a $54,000 prize up for grabs?

You say you've never had a lead like that before in eight seasons as a pro? Now, in a day you can win as much as you've ever made in a season.

Koch's chance more glory in the final round are excellent.

His 15-under-par total of 201 is well ahead of Fiori (67--205) and George Burns (70--206), as well as Lanny Wadkins (70) and Tom Purtzer, who are tied at 207.

Big names lurking on the periphery include Floyd (69), Kite (72), Calvin Peete (70) and Tom Weiskopf (70) at 208 and Nicklaus (69) at 209.

Koch, who could break Doral's tournament record of 270 with a 68 in the last round, got the Monster's merciful message quickly this overcast, breezy day as he birdied the first two holes. Then, things really got good.

At the fourth tee, Koch got out a new ball on the 185-yard par-3 hole over water; his five-iron shot was struck so purely that playing partner Kite, the Vardon Trophy winner, said, "Good lookin' shot."

When the ball landed 10 feet short of the hole, rattled the flag stick and went into the hole for an ace, Koch was certain it was his day.

When Koch landed after what he he estimated was a "three-foot" standing high jump, his first words were, "Thank you." He was addressing Kite, but, after the good fortune he had, perhaps Koch should have been looking higher.

Thereafter, nothing could deter Koch. When he got so excited by his "1" that he missed the next three greens, Koch steadied himself and chipped stiff every time to save par.

"The all-exempt tour has also made a big difference," said Koch.

"(In the last tournament of '82) I was sitting right on the 125th spot (the cutoff for an exemption). After all my (golf) years in school and on tour, I knew I had to perform."

Koch responded with his only top five finish of the year. His reward: a sane life. "Golf is fun again. Finally I can relax and get squared away."

And enjoy his perfect day.