George Allen's face and frame sagged in disappointment as he watched his Chicago Blitz blow a 38-17 fourth-quarter lead to lose, 44-38, to Philadelphia in overtime today. He walked from the field in bitter silence after Kelvin Bryant dived from the one-yard line over the goal line for the winning touchdown and a berth in next week's U.S. Football League championship game.

Allen tried to betray little disappointment after the playoff. Although his defense allowed 24 points in the fourth quarter and Philadelphia provided seven turnovers, Allen said, "I told my team I was proud of them. The season's over now."

On Sunday, the Michigan Panthers will entertain the Oakland Invaders (1:30 p.m., WJLA-TV-4), and the winner will play the Stars at Mile High Stadium for the league's first championship.

But Allen, who has said he dies a little when he loses, will have to live with one of the deepest disappointments of his career. Perhaps an incident which took place Friday best illustrates Allen's hunger to win and his unwillingness to sympathize with defeat.

Allen was jogging with a television reporter near the airport here when the greyhound- sleek, 61-year-old coach turned to his partner and interrupted his own monologue.

"Did you see that dead dog back there on the side of the road?" Allen asked. "Know why he never made it across the road? That dog was too fat, that's why!"

Allen was fiercely determined to lead his team across a treacherous street today; Philadelphia's 15-3 regular season record was the league's best. But the Blitz, though well-conditioned, faded when it needed to shine.

From the start, Allen paced the sidelines with his usual frenetic energy in front of 15,684 at Veterans Stadium. He shook more hands than Tip O'Neill at a barbecue. He implored his defense to stop Bryant, though the league's most valuable player ran for 142 yards and two touchdowns.

Early in the first quarter, Stars quarterback Chuck Fusina saw his pass fall into the hands of defensive back Virgil Livers.

Quarterback Bobby Scott, who came to the Blitz in a trade with New Jersey after Greg Landry broke his ankle, responded with an 81-yard drive that ended with Kevin Long diving over for a 7-0 lead.

Several minutes later, Luther Bradley intercepted Fusina on Philadelphia's 29 and returned the ball 10 yards. After two runs by Long for 13 and three yards, Scott himself ran three yards for a 14-0 lead with 13:21 left in the second quarter.

The teams then exchanged touchdowns, a 10-yard run for Bryant and then a deft, 12-yard scoring pass from Scott to Trumaine Johnson following a fumble by Fusina.

But with two minutes left, and the score 21-7, the Stars pulled closer with a stunt. Runs of 21 and 19 yards by Bryant helped Philadelphia drive to the Chicago 12 with 48 seconds left in the half. Fusina took a deep snap from a shotgun formation and then handed off to Allen Harvin.

Harvin, with the fluid motion of a man trying to throw a bed out a window, heaved the ball to Fusina, who flopped into the end zone for the score.

But an early fumble by Harvin on the fourth play of the second half helped widen the gap. Ed Smith recovered for Chicago on the Philadelphia 34. Spencer's precise pass to Mack Boatner was good for a 12-yard score and a 28-14 lead with 8:01 left in the third quarter.

Less than three minutes later, the Blitz took advantage of another fumble, this time by Scott Fitzkee after a pass reception, and increased its lead to 31-14 on a 32-yard field goal by Frank Corral.

After David Trout hit a 42-yard field goal, Fusina threw his fourth interception of the game, a mistake which led to a one-yard scoring run by Chicago fullback Kevin Long. With 12:04 to play, Chicago had a seemingly insurmountable 38-17 lead.

Seemingly.

Fusina rid himself of his hesitation and threw three straight scoring passes to Fitzkee for 17 yards, Jeff Rodenberger for two yards and Tom Donovan for 11 yards and a 38-38 score. "They stuck with me," Fusina said. "They were saying 'bring us in, bring us in.' "

The final score to Donovan with 50 seconds left in regulation came at the end of a 10-play, 70-yard drive. The Philadelphia offense simply blitzed Chicago, and the Blitz was unable to respond with a score of its own.

On his way out of the stadium, cardiologist and Chicago owner Ted Diethrich said, "All of a sudden we got so damn conservative. I don't know why."

Philadelphia's momentum continued even with the coin toss for the overtime period. The Stars received, and on a 14-play drive they had a third-down situation only once as Bryant, who had rested for much of the second half, took command and scored the final points.

"Today was not to be for us to win," said Allen, the former Washington Redskin coach. And then he turned away and the heavy metal doors slammed behind him.