It was difficult to say which was the biggest upset of the college football weekend: No. 19 Alabama's victory over defending national champion and No. 11 Penn State, or No. 16 Notre Dame's trashing of No. 9 Michigan at Ann Arbor, or No. 2 Nebraska's sidestep of No. 3 UCLA by, of all things, the pass.

With Bill Curry making a controversial big game debut as coach of Alabama, not many expected the Crimson Tide to win in State College, Pa., much less devastate the Nittany Lions, 24-13, on the merit of Bobby Humphrey's 220 yards rushing and 57 passing. Humphrey established himself as a Heisman hope, the Crimson Tide proved it is to be taken seriously, and Curry showed he just may survive at one of the fiercest of football schools.

It was the kind of potential season-maker that will take considerable pressure off the Crimson Tide, which had labored under skepticism of Curry, coming over from Georgia Tech. "What this group had to put up with because of me would have destroyed the concentration of a lesser group," he said.

It had been two years since the Nittany Lions were whipped in the regular season. The loss ended the nation's longest Division I-A winning streak at 13 games, a regular season streak of 23, and 15 straight in Beaver Stadium.

"We have't lost in so long, I really don't know how to react," senior defensive lineman Matt Johnson said.

But this was not the same team that went undefeated the last two regular seasons. Penn State lost 15 starters, and the replacements frequently looked confused.

"I'm surprised at how poor we played," linebacker Trey Bauer said. "I expected better. We just have a lot of inexperienced talent and young guys who don't know how to play a tough game."

But Alabama also had little in common with last year's Ray Perkins-coached squad that went 10-3. Only nine starters returned. But there was a veteran offensive line that shoved Penn State around and keyed much of Humphrey's yardage. His big plays were a 73-yard scoring run and his 57-yard halfback pass to set up new quarterback Dave Smith's one-yard touchdown run.

Humphrey's individual rushing bettered that of any whole team against Penn State last year. His yardage was the third best ever against the Nittany Lions, behind Tony Dorsett's 224 for Pitt in 1976 and Ted Brown's 251 for North Carolina State in 1977.

Humphrey should soon surpass Johnny Musso as Alabama's all-time rusher. He came into the season 687 yards shy of Musso's 2,741, and after two games is only 383 yards behind.

Another coach who may have turned the corner was Notre Dame's Lou Holtz, who directed the Fighting Irish to a 26-7 victory marking Michigan's first loss in a home opener since Bo Schembechler took over in 1969.

Rarely has a Michigan team looked so ill prepared for a season. Like Penn State, the Wolverines lacked overall organization and were victimized by some general inexperience. They turned over the ball seven times, and Notre Dame converted four takeaways into scores.

Not even 128 yards from tailback Jamie Morris could save Michigan, which was 17-0-1 in home openers under Schembechler. The largest uncertainty for Michigan remains at quarterback, where Jim Harbaugh graduated. Demetrius Brown gave up three interceptions, and alternate quarterback Michael Taylor gave up another.

Nebraska's 42-33 victory was not surprising, since the Cornhuskers had thoroughly humiliated the Bruins in the last two meetings, 42-10 and 42-3 in 1983 and '84. What was intriguing was the manner in which they did it this time, going to a dazzling Steve Taylor-led passing game after UCLA hung within 14-10 at halftime.

Taylor's school-record five touchdown passes could have long-term implications for the Cornhuskers. If their running game develops the way it should, they will be a dangerously multifaceted team. But the Nebraska ground offense was a surprising source of irritation to Coach Tom Osborne, producing just 117 yards and four fumbles. The yardage was their second lowest this decade.

"I don't want to be a spoilsport, but 117 yards in 47 carries, that's abysmal, that's terrible, that's not even football," Osborne said.