A week ago, when Pete Rose's hitting streak stood at 37 games, Johnny Bench leaned against the Cincinnati batting cage, watching Rose distribute liners to all fields with a fine impartiality.

"Only 20 more games to go," drawled Bench. Both Rose and Bench broke up, laughing.

No sane ballplayer predicts or discusses in advance, a 20-game hitting streak, let alone a 57-gamer.

"I had 14 in a row when I was a rookie," said Bench. "Joe DiMaggio called me on the phone - honest - and said, 'Lay off, kid.'"

Just a week ago DiMaggio's 56-game streak was still so inaccessible that just mentioning it was a joke.

Now, the Yankee Clipper's colors are in full vieew and that piratical Capt. Rose is making for it.

Avast, Joltin' Joe!

The unsentimental statistics provided by the Elias Sports Bureau say that a career 311-hitter like Rose is still no better than a 21-to-1 shot to tie DiMaggio, 27-to-1 to suppass him, despite his laborious 43 games of groundwork.

However, considerable sentiment in baseball, some of it with hard facts to support it, feels that Rose has a far better chance than a paltry 27 to 1 to smash the most famous record on the baseball books.

For once, the gambler's instinctive line may be more accurate than the statistical pencil-pushers. Las Vegas bookshops have put Rose on the board at a mere 10-to-1 to break Joe D's record.

Part of that price is sentimental "hope-he-does-it" money. But part is good common sense.

Stacked in Rose's corner are his switchhitting, his new-found affection for bunting, his love of the limelight (and his experience in managing it), his reputation as a pressure player, the Red's second-division opposition for the next 13 games, and a modified Rose batting stance and grip that opposing teams have not yet figured out.

Add to that Rose's Cincinnati teammates, capable of batting around to get Rose an extra turn if he needs one.

"The key to my streak," said Rose, "is that I'm finally hitting well righthanded (after an early-season .230 slump).

Throughout his career, Rose has been - in Manager Sparky Anderson's words - "consistent batting lefty, but off-and-on right-handed."

Last season Rose caught fire batting right-handed, hitting .331 vs. .298 lefty. Nevertheless, Rose, over his whole career, still has been significantly better as a left-handed hitter - .318 to .295.

Now Rose has found the righthanded knack again, a la 1977, hitting .364 against southpaws over the duration of the streak.

"There are more good left-handers in the National League this year than ever in my career," said Rose. "I think the streak will go as long as I keep my right-handed hack (swing) intact."

Since Rose is hitting .402 as a lefty in his streak, he can be forgiven for thinking that no right-handed pitcher is going to put a collar on him.

"A switch-hitter is really two different players," said Philadelphia switch hitter Bud Harrelson. "That's what makes his streak doubly incredible. He's had to keep his lefty and his righty self hot at the same time."

A switch-hitting streaker faces a double-edged sword. If he's hot from both sides, he's twice as hard to stop. But he also is twice as prone to a slump - on one side or the other.

Rose's greatest advantage, however, is his near immunity to being worn down by pressure. So far, Rose has turned the heightened intensity of these days to his advantage, drawing energy from the tornado around him, rather than being drained as a lessgregarious, less-disciplined, less-experienced player would.

Rose has two other weapons - one no longer secret, the other still unpublicized.

The elder-citizen third baseman has unveiled his bunting skill this year, a talent long kept under wraps by the combative Rose who preferred line drives and thought of bunts as a psychological admission of inferiority to a pitcher.

His streak contains seven bunt hits, four of which have saved the streak.

Rose is not so delighted to discuss his other tactical changes. But he will not duck a direct question. Against New York in May, Rose choked up two to three inches on the bat "for the first time in my life" after a first-inning strikeout.

The result: three homers and five straight hits in his first game with the choke stroke.

"That proved to me that it didn't rob me of power," said Rose. His next discovery - perhaps the most important of his streak - is that he was striking out less than ever in his career - only 19 times in 463 plate appearances.

With his whiffs cut by more than 50 percent, Rose has been able to wait until the last second, lashing pitches to the opposite field more than ever.

"My bats are 35 inches long and 33 1/2 ounces," said Rose. "But I'm choking up so much that it probably doesn't weigh more than 31 ounces. I've choked up so high sometimes that my top hand was above the pine tar."

The book on Rose has always been: great breaking-ball hitter. Blow him away or pop him up with heat.

The choked-up Rose, with a bat that, in effect, weight no more than a curves, but slaps the fast bills with more authority than ever. With third basemen playing closer than before - to stop his bunts - Rose is thriving on the old "suck 'em in and slap it through" routine.

Rose also is standing deeper in the box and farther off the plate (from both sides) than anyone has ever seen him before. "I have to crouch more, so that I can still cover the plate," he said.

No one in the NL has figured out how to pitch to this slightly older and wiser Rose. The choked bat makes him quick on inside pitches; the deep crouch and initial stride toward the plate allow him to reach the outside pitch.

Rose's hitting system is no secret. The '78 model Rose is merely finetuned, not fundamentally changed.

After all, the Kansas City Royals - call them the Kansas City Clones - use seven, eight or even nine men in the same lineup who all look like miniature Roses.

Charlie Lau, the Royal batting coach, freely admits that Rose has always been the model for his Astro-Turf school of slap hitting: stand deep in the box, far off the plate, feet together, bat held flat, deep crouch, weight on back foot, "charge the plate," hit to the opposite field.

If DiMaggio was the classic standup hitter of the '30s' and '40s' power age, Rose is the prototype of the synthetic-field era of line-drive spray-hitters.

Rose's pursuit of DiMaggio is more than a player from one era challenging a great from another time. It is Rose's trend-setting style of the '70s, demanded by the changed conditions of the game, proving that it can match the standards of a simpler age of hitting.

For 16 years Rose has worked at refining the art of becoming what he calls "not a home run hitter, not a punch-and-July singles hitter, but something a little new - the doubles hitter who rips shots up the gaps and down the lines."

In every sense, Rose's great streak is a testament to his years of labor in the batting cage. Now, at 37, he has all his theories working at once.