Pasadena ? Michigan or Florida?

One will play Ohio State in the BCS championship game. The other will be ticked off at the maddeningly imperfect system used to crown a major-college football champion.

One thing’s for sure, a Saturday stunner shook up the Bowl Championship Series and made selection Sunday a whole lot more interesting.

With a chance to lock up a third consecutive trip to the title game, Southern California lost, 13-9, to UCLA in the biggest upset of the season and opened the door for the Wolverines or the Gators to play for a national championship.

“It is kind of a shock, but at the same time, they did a great job,” USC receiver Dwayne Jarrett said.

Not long after the Trojans let their opportunity slip away, Florida (12-1) made its final case with a 38-28 victory against Arkansas in the SEC title game.

So it comes down to this for the poll voters and computer rankings the BCS uses to determine which team plays for the national title – a Michigan-Ohio State rematch or Gators vs. the top-ranked Buckeyes in the desert on Jan. 8.

“Michigan already had its chance,” Florida freshman receiver Percy Harvin said. “I think we deserve a chance.”

For the first time since the BCS was born eight years ago, after all the regular-season games have been played, the championship matchup is anybody’s guess going into selection Sunday.

And at least one person who will help make the decision isn’t looking forward to it.

“I don’t feel real comfortable casting a ballot,” Ohio State coach Jim Tressel, who votes in the coaches’ poll, told ESPN. “I know we’re going to have to play one of the two, and I don’t want to make either of them mad.”