SAN FRANCISCO, DEC. 1 -- One week ago Sunday morning, the New York Giants awoke in a hotel across the river from Philadelphia. They had the arch rival Eagles on their minds, the NFC East title a victory from their pockets, and the football world impatiently waiting for what promised to be a historic date with the 49ers.

Nearly 3,000 miles to the west, the 49ers arose for their NFC West matchup with the Los Angeles Rams. Like the Giants, they began the day 10-0. Like the Giants, they needed only that day's victory to clinch their division. And like the Giants, they were expected to dispatch their foe to create the first Week 12 matchup of unbeatens in the NFL's 69 years.

But neither happened. The Giants got whipped, 31-13. The 49ers got whipped, 28-17.

And suddenly, the scenarios for Monday night's regular season Super Bowl at Candlestick Park -- the 10-1 Giants vs. the 10-1 49ers -- have changed.

"We're right in the middle of it," Bill Parcells said, referring to a December schedule that shows the 49ers, Vikings and Bills in succession. "Three quality opponents. Anything can happen."

Now, unless Philadelphia loses Sunday at Buffalo, the Giants can't clinch their second straight division crown Monday. Now, unless the 9-2 Bears lose Sunday at home to Detroit, both the Giants and 49ers will be in danger of falling into a tie for the worst record among the NFC division leaders. That would jeopardize a first-round bye in the NFC playoffs and home-field advantage if either advanced to the second round.

And no Super Bowl contender wants to be fighting a two-game losing streak in December.

"A loss can be healthy," Giants safety Dave Duerson insisted. "In our case it is. It doesn't hurt to refocus. The difference between good teams and great teams is the great teams keep their sights on their goals."

So Monday night's game at Candlestick Park is no longer simply a flexing of the muscles by two unscarred behemoths. It's no longer unique. While the winner might sigh, the loser will be forced to contemplate a third straight defeat.

"That's why when a team gets to be 5-0, 6-0 and everybody starts talking about what's in front of the team, it's really an exercise in futility," Parcells said. "Because so much changes so quickly."