MIAMI -- Drew Brees emerged from the locker room with a fresh cut under his chin and another between his eyebrows.
He made the Miami Dolphins look worse.
Brees and the unbeaten New Orleans Saints fell behind for the first time all season, then overcame a 21-point deficit Sunday to beat Miami 46-34.
The NFL's highest-scoring team topped 40 points for the fourth time and outscored the Dolphins 22-0 in the fourth quarter.
"There was no doubt on our sideline we would come back and win," said Brees, who threw for 298 yards. "They had given us their best shot, and we had played about as bad as we could play. All we had to do was string together a few drives and gain the momentum back. We knew it was going to happen, and it did."
NFL passing leader Brees had his worst day of the season, with three interceptions, a lost fumble and five sacks. But he led touchdown drives of 82, 79 and 60 yards on successive possessions in the second half to put New Orleans ahead.
Tracy Porter's 54-yard interception return then sealed the win for the Saints (6-0), who are off to their best start since 1991 and are the only unbeaten team in the NFC.
"It can be a season-defining win," linebacker Scott Shanle said. "This was a test we hadn't faced yet, and we couldn't be happier with the way we responded."
Brees threw for one touchdown and scored twice. After his 2-yard keeper with 8:35 left gave the Saints their first lead, he celebrated by dunking the ball over the crossbar.
"There are times in the game when a team just needs an emotional lift," he said. "I felt like I had to do something to get everybody hyped. The first thing that came to mind was to dunk it."
Fading at the finish, the Dolphins (2-4) fell 2 1/2 games behind AFC East leader New England.
"This was our game to win," Miami's Ricky Williams said. "We fought and we fought. They just fought harder at the end."
Williams carried only nine times but tied a career high with three touchdowns rushing, including a 68-yard run, the longest of his career. At that point, the Dolphins appeared en route to a stunning blowout.
By the time the Saints picked up their second first down 22 minutes into the game, Miami led 24-3. Against New Orleans, that wasn't enough of a cushion.
"With Drew Brees, it's like the score is 0-0," Miami cornerback Vontae Davis said. "We knew they would come back and that it would be a tough game."
Two Dolphins turnovers and an ill-advised timeout helped New Orleans back into the game.
After Davone Bess lost a fumble at midfield late in the first half, Marques Colston caught a 21-yard pass that was initially ruled a TD. When a replay review with 5 seconds left determined the ball should instead be placed at the half-yard line, the Dolphins called timeout.
With the Saints trailing by 21, coach Sean Payton sent his field goal unit into the game. During the timeout, Brees lobbied for a shot at a touchdown.
"I just told him I'd get it," Brees said. "I said, 'I'll get the touchdown. I know exactly what to do."
The Saints' offense returned to the field, and Brees plunged across the goal line to make the score 24-10.
New Orleans struck again barely a minute into the second half when Darren Sharper scored on an interception return for the third time this season. The 42-yard runback came after he snatched a pass that deflected off the hands of receiver Ted Ginn Jr.
The pace of scoring soon became frantic, with three touchdowns in less than three minutes. The Saints drove 82 yards for a score to pull within 27-24, but Miami's Brian Hartline turned a short pass into a 67-yard gain to set up Williams' third score.
Jeremy Shockey then broke two tackles on a 66-yard reception for New Orleans, and two plays later Reggie Bush scored from 10 yards out on a reverse, capping his run with a balletic leap near the pylon.
The Saints forced a punt and mounted the go-ahead drive capped by Brees' score, which made it 37-34. John Carney hooked the extra-point try wide, but he hit a 20-yard field goal with 3:23 left.
Trying to mount their own comeback, the Dolphins dropped two passes and committed two penalties before Chad Henne was intercepted by Porter on fourth-and-13.
Saints DT Sedrick Ellis left the game with a sprained right knee, and FB Heath Evans hurt his right leg. ... Dolphins CB Will Allen was sidelined by a knee injury. ... Miami's wildcat netted 30 yards in 14 plays. ... Carney became the fourth NFL player to score 2,000 points.