ATLANTA — Tampa Bay played like a team determined to take control of the weak NFC South.

Byron Leftwich played like a quarterback who won't be starting very long in Atlanta.

Jeff Garcia threw for two touchdowns, Ronde Barber returned a fumble for another score and the Buccaneers' defense completely stifled the Leftwich-led Falcons 31-7 on Sunday, another low for a franchise trying to recover from the Michael Vick debacle.

Atlanta (3-7) had won two straight with Joey Harrington at quarterback and actually had a chance to pull within one game of first place in a division where Tampa Bay (6-4) is the only team with a winning record.

It was a good day all around for Bucs. New Orleans and Carolina both lost as well, dropping to 4-6 and two games behind Tampa Bay with six to play.

In a highly debatable move, first-year Falcons coach Bobby Petrino decided to start Leftwich over Harrington, saying he was still the No. 1 quarterback after missing the last two games recovering from ankle surgery.

Playing behind a short-handed offensive line, Leftwich had one of the worst games in his career, completing 15-of-28 for 106 yards with two interceptions and two fumbles. Harrington took over late in the third quarter, but it didn't matter much by then with Tampa Bay already leading 24-0.

Earnest Graham ran for 102 yards, including a 26-yard touchdown. Garcia didn't have to do much with the defense manhandling the Falcons; he completed 10-of-20 for 159 yards, including a 44-yard touchdown to Joey Galloway that got the Bucs rolling.

The only solace for Atlanta was avoiding its first shutout since 2005. Harrington threw a 7-yard touchdown pass to Adam Jennings with 1:10 remaining and mostly backups on the field.

The Bucs were up 7-0 early in the second quarter when Leftwich tried to scramble from the pocket on his gimpy ankles and was hit from behind by Greg White, knocking the ball loose. Barber picked it up on one bounce and scooted 41 yards to the end zone without being touched.

At that point, the Georgia Dome crowd broke into cheers of "Joey! Joey! Joey!" Petrino decided to stick with Leftwich, and things only got worse.

Matt Bryant punched through a 23-yard field goal that made it 17-0 early in the third, and Leftwich's final play was another turnover. Gaines Adams hit the quarterback's hand from behind as he tried to throw, the ball fluttered in the air and defensive tackle Chris Hovan made a juggling interception at the Atlanta 27.

Three plays later, Garcia threw off his back foot under pressure and Alex Smith made a leaping catch in the end zone for a 21-yard touchdown, giving the Bucs a 24-0 lead and sending what was left of the crowd heading for the exits with nearly 5 minutes still left in the third.

Graham added to Atlanta's misery on the first play of the final period with his TD run.

Harrington was 16-of-20 for 139 yards, which might lead Petrino to reconsider his stance that Leftwich is the starter for the rest of the season as long as he's healthy.

Facing his former team, Atlanta's Warrick Dunn failed to become the 22nd player to rush for 10,000 yards in his career. He was held to 32 yards on 15 carries and is still 26 short of the exclusive club.

The Falcons rushed for only 49 yards.