The Los Angeles Dodgers and Philadelphia Phillies each obligingly capsuled their essences in on extra-inning thriller tonight: 4-3, Phils.

It was the injured, unsure, bullpen-beleaguered Dodgers yielding to the refurbished, belligerent, Rose-colored Phillies before 32,826 at the cacophonous Vet. . . the National League division champions of the East and West going in opposite directions from when last they met in earnest-six months and a continent ago in Los Angeles in the playoffs.

Then, each seemed determined to fulfill its historical baseball role. The Dodgers were headed to the World Series. The Phils were looking for a psychiatrist's couch.

Much has changed since then. The Dodgers have lost free agents Tommy John, Bill North and Lee Lacy; they have been plagued by nagging injuries to Reggie Smith and a half-dozen others.

The Phils have not only gained free agent Pete Rose, but traded for All-Star quality second baseman Manny Trillo and young fastballer Nino Espinosa.

Tonight's Phillie triumph-decided when Mike Schmidt singled home Larry Bowa from third with one out in the 10th inning off reliever Lance Rautzhan-was a perfect paradigm of the woes and joys of these two defending titlists.

All night, the Dodgers pushed into the lead. And all evening, the Phils came from behind-hardly their past habit against L.A.

"We seem to expect things to go right for us," said Philadelphia catcher Bob Boone. "A lot of pieces have fallen into place.

The Phillies, who have won nine of 11 for a 9-4 season start, have gotten supremely brilliant pitching. Again this evening, the Phil Hurlers shut down every major uprising.

Starter Randy Lerch, who once maximized every jam with wildness, continued to be the new, steady Lerch. His walkless performance left his total at three free passes in 30 innings. Twice he squirmed from difficulty by allowing mere sacrifice flies, to Dave Lopes and steve Garcey.

Once, had Lerch allowed nine hits, he might have fallen behind by five or six runs. Tonight the early deficit was just 2-3, a margin that Greg Luzinski erased with one home run swing against Dodger starter Andy Messersmith with a man on in the sixth.

Lerch was chased by consecutive first-pitch doubles to left in the seventh by Lopes and Bill Russell, giving L.A. a 3-2 lead. But as soon as Manager Danny Ozark went to his right-left Bullpen combo of Ron Reed and Tug McGraw, the Dodgers were dead.

That Phillie mos anxious to demonstrate that his club would no longer lie down tamely before the Ddgers was predictably, Rose.

Charlie Hustle drew three walks, led cheers and even tried to pick a fight with Messersmith by slamming him hard with a tag at first base, then getting in his face to tell him what he could do if he didn't like it. The two were separated by coaches and umpires.

When the Dodgers went to their bullpen, the cupboard was bare-not a Reed nor McGraw to be found.

Manager Tommy Lasorda compounded the problem with curious pitching-change decisions. Ahead in the eighth, 3-2, Lasorda called in a lefty, Jerry Reuss, to pitch to right-handed slugger Schmidt.

Managers are paid to know the detailed personal histories of their players, i.e., Schmidt has owned new Dodger Reuss all his life-taking him downtown for seven career homers. Of course, Schmidt rifled a gametying hit.

Lasorda's hook backfired once more when he pinch hit for his one effective reliever, Rick Sutcliffe (0.75 EAR) in the ninth. The Dodger lack of bullpen depth, with Terry Forster disabled, was obvious by the time the wild Rauzhan arrived. The southpaw walked Bowa and Rose to start the 10th, gave up a warning-track line out to Luzinski that advanced Bowa to third, then dished up the game-loser to Schmidt.

The Dodger fortunes to date were summed up by reserve catcher Johnny Oates. "How's it been going?" someone asked.

"It hasn't," he answered.

While the Phils have outscored their opponents, 61-41, this spring, the Dodgers have been on the short end, 77-69. With Smith and Ron Cey nursing swollen knees, the Dodgers have fallen to 10th in the league in hitting.

In his previous two years, Lasroda's clubs have jumped into first place with 22-4 and 13-5 starts. The current 8-10 mark is the first time his Dodgers have seen the dark side of 500.

"They're full of talent," Rose said of the Dodgers. "But there's no way in the world you can tell me that they've replaced Tommy John. It has to hurt 'em. No way I'd pick them to win their division. Gimme San Francisco's chances."

Give the Phillies their own chances.

Rose is hitting as usual (.298) and does not mind hurting his opportunities for his much loved 200 hits if batting No. 3 will help the team. The nimble Trillo, a master of the double play pivot, entered the night hitting .391.

When last sighted in October the Phils were dragging themselves off the Chavez Ravine turf after center fielder Garry Maddox had botched a line drive in extra innings. As Cey penguined across the plate with the pennant-winning run, the Phils left the final ball of the game sitting in the outfield grass untouched-as if the contaminated sphere has caught their disease.

Now, Maddox is batting .396. That's how long a memory The Mighty Burner has.

Just a month ago, the Philadelphia pitching rotation looked bleak after the offseason injury to Larry Christenson. Would ancient Jim Lonborg and Jim Kaat be revived?

So far, Kaat and Lonborg, symbols of desperation, have not pitched an inning, Espinosa, released from bondage as a Met, is 2-0 with a 2.25 ERA. Dick Ruthven has shaken arm problems and is even better at 3-0 with a 1.73 ERA. Southpaws Lerch and Steve Carlton (2.2) have done their share.

The Phillie staff already has five complete games. Last year, they did not reach that figure until mid-June.

April is never the month of truth. In baseball, that distinction belongs to September. Neverthless, this is the chilly month of potents. Enough said.