Atlanta — A backup quarterback denied Tennessee a spot in the Rose Bowl and really messed up the Bowl Championship Series.
Matt Mauck, filling in after Rohan Davey was injured, ran for two touchdowns and No. 21 LSU won its first Southeastern Conference title since 1988 with a 31-20 upset of second-ranked Tennessee on Saturday night.
The Volunteers (10-2) came to Atlanta hoping to complete their run for the Rose Bowl and a chance to win the national championship. Instead, they'll have to settle for the Orange Bowl, at best, or more likely the Citrus Bowl.
"We had a great opportunity to play for the national championship," running back Travis Stephens said, "but we failed."
Mauck, a 22-year-old freshman who spent three years as a catcher in the Chicago Cubs' organization, put LSU ahead for good with a 13-yard touchdown on the second play of the fourth quarter. He also scored LSU's first TD on a 4-yard run.
Another backup, Domanick Davis, finished off the Vols by diving over the top on fourth-and-goal from the 1 with 2:26 remaining.
"We just didn't play very well," said Tennessee coach Phil Fulmer, whose team joined the national championship race last week with a 34-32 victory over Florida. "We got here together. We lost together."
Now, who will go to Pasadena to face top-ranked Miami? No. 5 Nebraska was next in the BCS standings, despite a 62-36 loss to Colorado in the Cornhuskers' last game.
Simply put, the computers will decide. No. 3 Oregon and No. 4 Colorado are hoping to slide into the second spot. No matter what happens, there's sure to be plenty of controversy.
Tennessee could have made the call a little easier on the BCS by winning. But the Vols couldn't beat an LSU team that lost both Davey and star running back LaBrandon Toefield to injuries in the first half.
"Everybody believed in each other," LSU coach Nick Saban said. "Matt and Domanick did an outstanding job taking the place of two outstanding players in a crucial game. I couldn't be happier with the way they came through."
LSU (9-3) earns a spot in the Sugar Bowl against No. 8 Illinois with a truly remarkable upset, the final surprise in a regular season that ended a week later than expected because of the Sept. 11 terrorist attacks.
Nebraska, Florida and Texas all fell by the wayside in recent weeks. Now the Cornhuskers might be back in the national championship picture, even though they didn't win their own division in the Big 12 Conference.
After falling behind 17-7, LSU held the Vols to a field goal in the second half.
Stephens, who rushed for a career-high 226 yards in the upset of Florida, managed just 37 yards on 14 carries. He also had a crucial fumble that led to Mauck's go-ahead touchdown.
"Last week didn't mean anything tonight," Stephens said. "If we had won tonight, then last week would have meant something."
Kelley Washington had six catches for 103 yards in the first half but just three for 37 yards over the final two quarters.
Down 24-20, the Vols had a chance after a short punt gave them the ball near midfield. Casey Clausen completed a 17-yard pass over the middle to Donte Stallworth, but Demetrius Hookfin stripped the ball and Ryan Clark recovered the fumble for LSU.
LSU then drove 65 yards for the clinching score. Appropriately, Mauck and Davis did all the running for the Tigers, while the Vols made two more crucial mistakes.
Julian Battle had an interception right in his hands but couldn't hang on. Rashad Baker tripped up LSU's star receiver, Josh Reed, and was penalized for interference.
Toefield, who tied an SEC record with 19 rushing touchdowns, went out with an injured left knee. He gained just 18 yards.
In relief, Davis ran for 78 yards and Mauck contributed 43 yards on the ground, usually taking off from the shotgun. Mauck completed just 5-of-15 passes for 67 yards, but he was named the MVP.
"I was very nervous at the beginning," Mauck said. "But after I got in the flow, I felt OK."
Tennessee's last hope ended when Stallworth, trying desperately to pick up a first down, was dragged down by four tacklers at midfield with a minute to go.