The winds blowing through the streets of San Francisco come from the chilling reality that the National Football League's scepter might be passed on Sunday.

It wouldn't be accurate to call it an upset, should the Chicago Bears beat the defending Super Bowl champion 49ers (4 p.m., WBAL-TV-11) at Candlestick Park, although the oddsmakers favor the 49ers by four points.

The Bears are 5-0 and have proven they can beat you in a million ways. They took the Redskins on a 99-yard kickoff return by Willie Gault. They took the Vikings from eight points behind, when Jim McMahon entered and threw three scoring passes in an eight-minute span of the third quarter.

They took Tampa Bay twice, most recently last week, when All-Pro linebacker Mike Singletary led a magnetic defense in containing James Wilder, the NFL rushing leader, to 29 yards on 18 carries.

It's ironic that two years after the death of team founder George Halas, the Bears are playing all-out, ornery football -- Halas football, that is -- for the first time since 1963, when Halas coached them to the NFL title.

"To be honest, there isn't a whole lot said about Halas now," Singletary says. "But at the same time, Coach (Mike) Ditka has tried to exemplify the George Halas mentality: tooth-and-nail football."

The Bears are in cruise control. In fact, they haven't lost since the last time they came here, 23-0 in the conference championship game. The 49ers, however, are a 3-2 team that trails the Rams by two games and can't seem to find the clutch. They have been ambushed by inferior teams, Minnesota and New Orleans. They trailed abysmal Atlanta in the third quarter before rallying.

Cornerback Ronnie Lott, an All-Pro in all four of his NFL seasons, has been beaten for three touchdowns this year and has switched positions with free safety Dwight Hicks, another All-Pro.

And now come the reports that Coach Bill Walsh and quarterback Joe Montana -- the two-time Super Bowl Most Valuable Player -- are feuding over how the offense should be run. It seems that Montana wants more deep throws while Walsh is willing to accept numerous short throws. A misunderstanding that has been patched up, both say.

Last week, Montana threw 57 times -- five for touchdowns -- in a 38-17 pasting of the Falcons.

Walsh has made much of his legend by devising the first offensive 25 plays before the opening kickoff and then rarely deviating from the script. He hasn't exactly been Cecil B. DeMille this season, though: The 49ers have scored just 37 first-half points, 108 in the second half.

How many more 49ers defeats can there be before somebody mentions 1982? That was the last time the 49ers were defending league champs and that's when, in the strike-shortened season, they fell to 3-6.

"Nobody has brought up 1982 yet, but I'm sure it will come up," Lott says. "People will bring up the past and shake skeletons. It's gotten so bad around here that people are saying that Joe Montana's wife shouldn't have had a baby last week. One writer said that Joe works six months and is off six months and that he should know when to plan to have a baby."

Lott paused and added, "I didn't know that love worked that way."

The 49ers were at their best three weeks ago when they dismantled the Raiders, 34-10. Running back Roger Craig has been brilliant for San Francisco, running for 271 yards and catching 33 passes for another 401 yards. The 49ers' pass rush has produced 24 quarterback sacks, near the top of the league. The bottom line is that the 49ers' potential remains Super Bowl strong.

Two of the Bears' most vital defensive players -- end Richard Dent (injured hip) and tackle Dan Hampton (injured ankle) -- are expected to play.

Singletary thinks they'll be needed. "We'll have to play a flawless game to win," he said.