On any day, baseball is a game of instantaneous decisions and tantalizing inches. In the fifth game of the World Series today, baseball at its highest level became a game of fractions of inches.

The Philadelphia Phillies will call themselves the Comback Kids, and all manner of other giddy nicknames, after their stirring two-run rally in the ninth inning today to beat the Kansas City Royals, 4-3, and tilt this Series back their way once again, three games to two.

The Phils and their fans will talk of Mike Schmidt's leadoff single and Del Unser's pinch-hit RBI double and Manny Trillo's game-winning two-out hit in that thrilling ninth inning. And they will praise Tug McGraw for his three valorous innings of relief and the way he worked out of a bases-loaded-with-walks jam in the ninth.

What the Royals will remember, however, is the way Schmidt's ground smash rolled out of George Brett's glove at third as he sprawled on his face in a portrait of near-miss agony.

And how Unser's one-hop bullet went right past immobile first baseman Willie Aikens, who actually moved out of the way to try a fancy sweeping grab. What is it that Unser has on first basemen that they can't catch his hard grounders in the fifth games of post-season series? The Houston Astros are still muttering about an almost identical play.

And finally, Kansas City will think of the way Trillo's liner hit squarely in the glove of losing pitcher Dan Quisenberry's glove, then rolled slowly away as Unser sped home with the winning run. "It hit me in the glove and the bare hand both. Next thing, it was rolling by me . . . They never hit a ball more than 75 feet in the air off me, and they win," said Quisenberry, despondent and for the first time, not a quipster. "The ball was playing hide and seek. It just wouldn't find our gloves."

That top of the ninth was a mere fragment of the Royals' torment. Aikens, gone from hero to goat in a day, made one of the most horrendous errors in Series history today to cost his team a run. He nonchalantly caught a soft flip from starter Larry Gura on a bad back-to-the-mound bunt by Bake McBride in the fourth. McBride was out by 15 feet. A lazy, sleepy little play. But Aikens' big, clumsy foot was one inch, maybe less, from the bag. Instead of shuffling or jabbing his brogan a millimeter or two, he picked up his size-12 clodhopper and smashed it into the bag. In that additional split second, McBride had arrived. Tie goes to the runner.

The next batter, Schmidt, hit a 440-foot home run over the center field fence.

Yes, that was one run. And how about sluggish Darrell Porter being waved home from first base by Coach Gordy MacKenzie on Willie Wilson's sixth-inning double off the right field fence? That's a gamble you only pull with two outs, never with one out. For the second time in this Series, Porter was out from here to Topeka. At least this time he slid.

Just as Game 3 was a contest that the Phils lost more than the Royals won, so this shadowy twilight affair was a portrait in Royal profligacy. In Game 2, K.C. had 19 baserunners, scored just four runs and lost. Today, they had 17 men on base, stranded 13 and ended seven of the nine innings with men left in scoring position. Even when the Royals scored, it seemed a sort of minimal art. Big rallies became little one-run affairs as Brett drove in a run with a harmless fifth-inning ground out and U. L. Washington tapped a sacrifice fly to left in the sixth. Even the Royals' one loud blast -- a homer to open the sixth by Amos Otis, who is now 11 for 20 with three homers and 22 total bases -- was a solo blast and brought minimum returns.

When Jose Cardenal, one of those hound-faced, long-suffering journeymen synonymous with bad teams and defeat, struck out swinging with the bases loaded to end the game, it was just the culmination of a Royal flush of failures.

Two on and none out with the top of the order coming up in the third -- the Royals get nothing.Men at the corners in the fifth and Hal McRae hits a foul fly. TV replays show that McBride probably trapped it off the wall. But McRae is called out. Nice play. Close call. But fractions of an inch, again.

Normally, a team ought to be decimated if it endured what the Royals did today. And a club that won such a battle should exult that the tide of warfare had turned decisively.

The Royals should feel that this Series trickled away from them today as those ground balls rolled out of the gloves of Brett and Quisenberry.

And the Phils, who now return home, should feel that the rock of their interminable team history has been rolled away from the cave and they are finally free to walk into the sunshine of a championship season. After all, they have their aces -- Steve Carlton and Dick Ruthven -- scheduled for the sixth, and, if necessary, seventh games. Somehow, they have started callow rookies in the first and fifth games -- Whirlybird Walk and Marty Bystrom -- and escaped with wild and woolly wins.

However, in the aftermath of this game, both teams spoke only of their exhaustion, of how they don't know if they can persevere through another of these nerve-wracking games that is neither masterpiece nor slapstick but merely the most brutally draining of games between two solid, but limited, teams ill suited to quick kills.

If this Series goes to a seventh game, the fantasy recurs that it will be called in the 50th inning, tied 3-3, after both teams have left 100 men on base. These teams set the stage continually and torment each other with strategic decisions, then fizzle like a torch thrown in water.

"We can never do anything the easy way," said Phillie Bob Boone. "I hope for once we can on Tuesday (in Game 6)."

"I'm getting gray hairs," said McGraw. "We've had 10 straight post-season games and every one has been a one- or two-run game that went down to the last pitch. They keep advertising that CPR (cardiopulmonary resuscitation) here and I'm about ready for it."

"I'll be so glad when this is over," said Schmidt, hitting .389 with two homers and five RBI and finally looking like an October hero. "It burns your mind out. On every pitch, you have to fight the freaky thought that creep into your mind when you get tired. I just say to myself over and over, 'Hit it to me . . . hit it to me.' That drives out the little negative demons."

"When does it end?" asked Larry Bowa. "There's not much of me left. Pete Rose told me that whichever team gets the third win first has the hammer and usually wins. I guess Pete knows. I wouldn't. I haven't been here before."

Neither of these teams has, and they are playing like it.

These clubs swing from the sublime to the ridiculous, showing the best of themselves, then suddenly succumb to a pressure so insidious that even after it has done its work the players don't know what has happened. George Brett, for instance, struck out twice against McGraw -- the first time this season that he has struck out in consecutive at bats against the same pitcher. The second time, in the ninth with the tie run on first, he fanned on three pitches, taking the third. "I just couldn't pull the trigger," he said. "I don't know why."

Each player fights his interior devils differently. Royal gold glove Frank White is hitting .095, but he made four splendid defensive plays today and might have been the hero, but for those other K.C. gloves of lead in the ninth.

"Strange things happenin'," said McRae. "We've blown three leads in games we'd normally have won. Hell, we could have won five straight."

The emblem of this Series may be Aikens, the slugger who has had the greatest and worst moments of his career within a few hours. On Saturday, he was the man with four Series home runs. No one noticed the two routine one-hop throws that skipped past him. Today, he let another low throw (by Brett) scoot by him. He made the one-inch error that preceded Schmidt's homer. And, with a Series in the balance, he actually moved out of the way of Unser's smash in the ninth, trying to make a fine flourish of a grab to start a double play, instead of just parking his 230 pounds in front of the ball and taking his lumps.

"I thought my foot was on the bag," said Aikens, his face a stunned mask, his eyes as blank and withdrawn as they were sparkling and happy the day before. "On the other ball . . . it took a bad hop . . . I think . . . not too many guys can make that play . . ."

Aikens grew quiet, looking straight ahead. He was seeing the flip side of fame. This morning, his picture covered the front page: standing tall, he was waving his hat to the crowd as they gave him a standing ovation.

Every Phillie, every Royal, now knows this chilling feeling. They wanted so much to be here. The Fall Classic -- what idyllic fun. And now, the World Series is eating them all alive.