The last time the San Francisco 49ers were defending champions of the National Football League, they finished 3-6 in the 1982 strike season. It's almost a spooky coincidence that they are now 3-4.

De'ja , what?

San Francisco has lost to Minnesota, New Orleans, Chicago and Detroit. The 49ers have turned the NFC Central Division into dragon-slayers.

The 49ers' all-pro offensive guard, Randy Cross, was quoted after the 23-21 loss to the Lions Sunday, "(We're) past surprise really, past shock. 'Disgusting' is the word that comes to mind."

Consider these remarks by 49ers Coach Bill Walsh:

"There is a lot of notoriety when you win the Super Bowl, then you are expected to come back, make the full sacrifice again and you just don't see people doing that . . . After reaching the ultimate, you can't help but take a day off."

"In the fourth quarter -- the telling part of the game -- we were losing by a field goal."

"They (49ers' defense) weren't jarring people like they used to."

"The year before, (49ers players) would have ignored the same injuries and played with them."

On the San Francisco offense: "People got a lock on us."

Now consider this: Walsh made these statements about the 49ers' collapse in 1982. But they apply, with only minimal qualification, to this season as well.

No, the San Francisco defense has not been tackling as in the days of helmet-rattlin' yore.

In San Francisco's 18-1 sprint through last season, only two opposition running backs (Atlanta's Gerald Riggs and Pittsburgh's Frank Pollard) rushed for 100 yards in a game. Three have done it on the 49ers in just seven games this year -- New Orleans' Wayne Wilson, Chicago's Walter Payton and Detroit's James Jones.

Ronnie Lott, the all-pro cornerback, was beaten for three touchdowns and coaches switched positions for Lott and all-pro safety Dwight Hicks.

Fred Dean, once the most feared pass rusher in the league, has the same number of sacks this season as he did at this time last year: none. And Dean had an alibi last season when he held out until the 12th week.

When Detroit's Jones plowed for 116 yards on 30 carries Sunday, defensive linemen Dean and Manu Tuiasosopo and linebackers Todd Shell and Ron Ferrari all headed to the sidelines injured. These things didn't happen to the 49ers of '84.

It's unlikely that opposing defenses have gotten a lock on Walsh's multiple-formation offense. It is irrefutable, though, that quarterback Joe Montana has been unable to produce the same quantity of big plays as he has in the past.

Montana has had three yardage-poor games: 120 (New Orleans), 160 (Chicago) and 97 (Detroit), the last his lowest total since his rookie season of 1979. Montana had stomach flu Sunday, so affecting him that he was replaced by Matt Cavanaugh as the 49ers began their last drive on their 12 with 1:37 to play. Needing a field goal, they didn't get it.

Some have questioned Montana's ability to throw deep; his longest completions against the Bears and Lions covered 16 yards.

"(His receivers) are dropping the balls when sometimes they shouldn't. Montana doesn't seem to have as much time to throw as he had last year, either," Wayne Fontes, Detroit defensive coordinator, said yesterday.

"I think (pass rushers) are getting to Montana more than in the past. People are trying to contain him because he's very dangerous when he gets out of the pocket."

In 1984, Montana was sacked 27 times in 16 games. Now, it's 25 times in seven games.

And in the 26-10 loss to Chicago, 10 of the 13 penalties against the 49ers were whistled against offensive linemen -- four on Cross.

The 49ers' ball-handling has been poor, too. They suffered five fumbles (seven turnovers in all) in the loss to the Vikings. The team's 1984 turnover differential: plus-16. In 1985, minus-four.

Detroit often deployed five defensive backs on first down. "We tried to take away their passes underneath because they've had great success throwing to the backs and using short crossing patterns," Fontes said.

"Everyone knows (running back Roger) Craig is Montana's outlet. In certain defenses, we tried to take away Craig," said Wade Phillips, New Orleans defensive coordinator.

"We also tried to keep him from running to his right side. He had a lot of success in the Super Bowl, scrambling to his right side. We sagged off and tried to keep him from throwing the deep pass.

"Recognition," Phillips added, "is the key to good defense. Since we play the 49ers twice a year, we know what their receivers like to do and we know where Montana likes to go with the ball a lot."