The Baltimore Stars celebrated Monday night's U.S. Football League playoff victory over the New Jersey Generals by driving to Philadelphia. That got them to bed by about 4 a.m., and they didn't sleep in this morning.

What they did, pardon the yawns, was go right into meetings to get ready for Sunday's playoff game in Birmingham against the Stallions. After the all-day meetings and film sessions, Coach Jim Mora's one concession to Monday night's 20-17 victory was to give the players Wednesday off.

The Stars will have a short week of practice, and the Stallions are the Eastern Conference champions. The Stallions have beaten them twice this season, 7-3 and 14-7, when the Stars were in the middle of an offensive slump.

Although Monday night's victory showed signs of resurgence in the defending league champions, it also was an indication that the Stars might not have yet solved their offensive problems.

"They feel good about the win, but they're already looking at Birmingham," Mora said. "It's nothing new. We've been here before, and there are still games left."

There was some afterglow left, though. The Stars stopped a second-half comeback by the Generals, and Garcia Lane's two spectacular punt returns helped win the game.

The game had been talked up as one that would either be a low-scoring affair, or a field day for the Stars' Kelvin Bryant and the Generals' Herschel Walker, the premier backs in the league. Baltimore's second-ranked defense and New Jersey's seventh-ranked unit got the better of the exchange.

Bryant was limited to 54 yards on 18 carries. Walker gained 66 yards on 25 carries.

The Generals had 267 yards in total offense; the Stars were held to 61 yards in the second half and 177 for the game. They managed only 85 net yards rushing and 92 yards passing, the second time in franchise history they had been held below 100 yards in both categories.

That made Lane's two first-quarter punt returns seem even more important on the day after. The first was for a playoff-record 91-yard touchdown. The other was a 35-yarder to the Generals' 20 to set up Chuck Fusina's five-yard touchdown run.

The last time the Stars had been held to such low offensive totals also was against the Generals, in a 10-3 loss in May when quarterback Doug Flutie scored on a last-minute scramble. But he was designated to the developmental squad Monday, and under league rules both starter Ron Reeves and second-string Fred Hessen would have to have been hurt before Flutie would have been allowed to play.

"I would love to have played," said Flutie, still recovering from a broken collarbone. "I question the decision now, but it was made in my best interest. Down the road, I'm sure it was the best thing."

The Generals' loss means that the USFL's most visible team and its most notable stars, Walker and Flutie, are on the sidelines for the rest of the playoffs. Memphis and Oakland meet in the other semifinal game. With a 15-month offseason ahead before the move to a fall schedule in 1986, the league could have benefited from a more glamorous matchup.

The game was viewed by only 26,982 fans, the smallest crowd at Giants Stadium this season and a shockingly small one for a playoff. It likely was in part a result of the absence of Flutie, and the 9 p.m. kickoff.

League officials expressed concern that they will have trouble marketing the championship game at Giants Stadium July 14 without a home-team draw. The turnout probably would be particularly low if the two Southern teams, Memphis and Birmingham, were the championship matchup.