The once-mighty Southern California Trojans could be about to fall.

After going 40 and being ranked No. 1 in the nation, the Trojans have lost three times in the last four weeks to Alabama. Notre Dame and California. The perennial Pacific-eight champions are reeling. They have fallen from the national ranking altogether and in a tie with Washington and UCLA for second place in the conference with 3-1 records, a half-game behind Stanford, 4-1.

"We've got to stop analyzing all of the things that have gone wrong," coach John Robinson said. "We've become a grim football team the last two weeks. We have to start concentrating on what's right. We're a good football team in a slump. Our plan is to relax. The sun comes up every day.

We've been worrying too much about ourselves and haven't had much fun.

"There are no easy answers, but our problems aren't insoluable. We know we have to win our next three games. If we do, we'll go to the Rose Bowl."

That won't be easy. Those three games are against Washington in two weeks then UCLA. The toughest test of all, however, could be today when the surprising Stanford Cardinals bring what they call their "explosive ball control offense" into the Los Angeles Coliseum to challenge the Trojans.

Stanford can go to the Rose Bowl if it beats USC and then beats California Nov. 19 and if Washington, the only conference school it has lost to loses to either California today, USC next week or Washington State the following week.

Win or lose, the Cardinals have been one of the surprise teams in the nations this year. They have a 6-2 record overall. Their only losses were to Washington in Seattle and at Colorado in their first game of the season. They have beaten Tulane, Illinois, Oregon, Oregon State, UCLA and Washington State. They have done it mostly with an unusual offense by first-year coach Bill Walsh.

Before coming to Stanford, Walsh was the offensive coordinator for the Oakland Raiders, Cincinnati Bengals and finally the San Diego Charges.

The Stanford offense is directed by quaterback Guy Benjamin, the nation's leading college passer.

While such ball-control teams as Ohio State. Michigan, Texas and Oklahoma run down the opposition's throats five yards a carry, Stanford maintains possession of the ball by having Benjamin throw it.

"Ball control means controlling the ball so the other team can't have it," says Walsh. "There's no rule on how you do it."

Benjamin, a 6-foot-4, 202-pound senior from Serulveda, Calif., is averaging a whopping 224 completions a game and throws every type of pass imagineable - square-outs, square-ins, slants, streaks, flys, flares and screens.

He missed the UCLA game with a bad knee. But he has completed 157 of 244 passes for a completion percentage of 64.9 and has thrown for 1,878 yards and 16 touchdowns with only eight interceptions.

Benjamin's top receiver is 6-3 James Lofton a world-class long jumper with a mark of 26 feet 9 inches. Lofton has 41 catches for 720 yards and 10 touchdowns.

Both Benjamin and Lofton could be No. 1 picks in the prop draaft, as is 6-6, 272-pound offensive tackle Gordon King.

Most of the running is done by 5-8, 170-pound freshman Derrin Nelson. He has ruled for 742 yards averaging 5.7 yards a clip and has three touch downs. He has caught 39 passes for another 419 yards and three more TDs and is fourth in the nation in running.

The Cardinals have their problems on defense . They are seventh in the conference against the rush and have been burned by beg plays week after week.

"Our hope is to outscore them (the Trojans) and then hang on," Walsh said.

In other games today, Clemson and North Carolina play in Chappel Hill. The winner will clinch at least a tie for the Atlantic Coast Conference title. Clemson goes into the game with a seven-game winning streak after an opening loss to Maryland.

No, I-ranked Texas plays at Houston while second-ranked Alabama challenges Louisiana State in Baton Rouge.

Third-ranked Oklahoma is at Oklahoma State and No. 4 Ohio State visits Illinois.