MIAMI — For most of the first half, the New Orleans Saints could hardly make a first down.

Later there was no stopping them, as usual.

The unbeaten Saints overcame an early 21-point deficit, mounting touchdown drives of 82, 79 and 60 yards on successive possessions in the second half to overtake the Miami Dolphins 46-34 Sunday.

NFL passing leader Drew Brees had his worst day of the season, with three interceptions and five sacks. But he scored twice, the second time on a 2-yard keeper with 8:35 left to give the Saints their first lead.

Tracy Porter's 54-yard interception return sealed the win for the Saints (6-0), off to their best start since 1991. The league's highest-scoring team topped 40 points for the fourth time.

Miami (2-4) fell 2½ games behind AFC East leader New England.

The Dolphins' Ricky Williams carried only nine times but tied a career high with three touchdowns rushing, including a 68-yard run, the longest of his career. By the time the Saints picked up their second first down 22 minutes into the game, the Dolphins led 24-3.

It was the first time the Saints had trailed this season.

Miami then let them back into the game with two turnovers. 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.

The Saints then decided to run another play rather than settle for a field goal, 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.

Brees came into the game with two interceptions and four sacks all season, but the Dolphins mounted a fierce pass rush early. And the Saints looked sloppy at the start — by the time they ran their fifth play, they had been penalized twice for false starts and once for delay of game.