Pete Rose, master of the cleanly defined act, enemy of subtletly, prefers his diamond universe kept simple like his perspective on life in general.

Tonight, for his Cincinnati homecoming, Rose could not have his way. His adopted Philadelphia Phillies lost for the eighth time in nine games, 4-2, as Rose went 0 for 4 amidst a confusingly rich and ambiguous crescendo of mingled affection and boos.

For the 46,968 fans in Riverfront Stadium, Rose's first appearance here in a blue Phil uniform was a disturbingly complicated and murky matter for the emotions.

No one felt it more acutely than Rose, who arrived at the park five hours early and spent the day building an uncharacteristic wall of noncommital dullness around himself.

"I'm not an emotional person," he said, long before the media mobs appeared. "I'm a little bit afraid of myself. I don't want this thing to sneak up on me and get me too emotional."

Rose need not have worried. He was given standing ovations, generously mixed with an undercurrent of boos, twice - first, when he was awarded the 1978 Red' most-valuable-player trophy, before the game, then again when he opened the contest by lining out hard to center field.

Rose was obviously much relieved by his generous reception.

"Well," he began, picking up a microphone at his postgame news conference, "it sure was nice hitting in my 45th straight game tonight."

When the laughter stopped, Rose became subdued, almost somber by his bubbly standards. "It was exciting ... the ovations. You never know what to expect from baseball fans. I didn't want to think about what they'd do and then be dissapointed.

"I didn't want to damage those 16 years of memories here, 'cause, ya know, I understand that they want to see me lose now, since I'm wearing this here gray Phillies uniform," said Rose, looking down at his jersey."Oh, it's blue isn't it . . . I haven't been a Phillie as long as I was a Red.

"I understand that now I'm a Reds' opponent, and not just any opponent but maybe the most hated one, since I left as a free agent. Yeah, I understand that. That song they play in the seventh inning - "Root, root, root for the home team" - well, nobody does that no better than us folks from Cincinnati."

Rose refused to be drawn into the debates about just how warm his reception was. To the eye, the huge majority of the fans were standing and clapping for his first appearances. But to the ear, the vocal minority of boo-birds made the reception sound close to a love-hate standoff. During game situations, Rose was roundly booed in every at-bat, then cheered after he made outs.

"I couldn't tell how they responded," said Rose. "My hair's pretty long over my ears. I couldn't hear as good as I should."

Rose shook hands with his nemesis, club President Dick Wagner, during batting practice, but could not resist a few quick jabs.

"Some players told me that the Reds at first refused to let me accept the MVP award tonight because they were scared to put a microphone in my hand with a full stadium in my home town," Rose said with a grin.

"Now Dick Wagner knows I'm not going to do anything bush or say anything real bad about him in front of 50,000 people. I might tonight at home in front of my wife . . ."

Rose's remarks were short and tame, mere perfunctory thanks.

"Mr. Wagner and Mr. (Louis) Nippert (owner) were both smilin' tonight . . . especially when they announceed the attendance," added Rose.

Perhaps it was proper that Rose flied out strongly to center twice, then dribbled out weakly to the infield his last two times up. After all, this was not his proper stage, not an evening for simple heroics.

In a fitting anticlimax to this sloppy, drab game, Rose died in the on-deck circle with the potential tying runs on base in the ninth.

"Sure, I wanted to get up there and hack," said Rose. "I ain't afraid to fail."

In some ways, this Rose Affair had a harmless, backyard-barbecue flavor. Rose entered the game hitting a torrid .355, while his replacement, Ray Knight, was batting .339 for the Reds.

All the potential barbs and bad feelings were submerged under those two healthy statistics. No one could pester Rose about old age, free-agent defection or being overpaid. And no one could rip the Reds about how Rose's absence was ruining them.

"I guess Wagner was right about Ray (Knight)," said Rose. "Dick and I did a lot of things that the other didn't appreciate, but lets let that lie . . ."

If this game showed anything - besides being a Rose theatre - it was Phils and Reds. No pennant-race conclusions should be drawn from this skirmish since both lineups were littered with names like Aviles, Harrelson, Unser, DeFreitas and Kennedy, which will never reach the box scores when the stars get healthy in a week or two.

The Phils were in such bad repair that, before Del Unser and Garry Maddox tied the game at 2 with back-to-back homers to open the seventh, the Phils had been shut out of an astronomical 39 consecutive innings - a club record that was only nine shy of the major league mark.

This game, cluttered with scrubs, was decided when the Phils' reserve second-basement, Rudy Meoli, kicked a grounder with two outs and the bases loaded in the eighth to let the Red's two deciding runs cross the plate.

So Rose's grand return devolved into a slapstick evening of balks, booted dribblers and colliding infielders. In fact, one Phil - Ramon Aviles - flew out to right field only to discover that the umpire had called time just before the pitch. Granted a reprieve, Aviles was removed for a pinch-hitter - Bake McBride - who singled on the first pitch. That may have been the evening's only baseball landmark.

"It was a good night to put to behind me," said Rose. "That's just the way things went down on one day - June 1.

"Now I can go back to playing the game just like I normally do," said Rose. "I can get out of this darn 1-for-15 slump i'm in. Get up early for some BP.

"Maybe I'm due for a big game. After all, there were only 50,000 people watching tonight," said that uncomplicated man who possesses the kind of supremely efficient guile that only comes from a profound form of common sense.

"Tomorrow afternoon's the TV game of the week. It's be 50 million."

Pete Rose gave his normal, relaxed smile for the first time of this complex day. His next stage was already set.