NEW ORLEANS — Phil Dawson kicked a 35-yard game-winning field goal in overtime to defeat the New Orleans Saints, 27-24 at the Superdome on Sunday.

Linebacker Ahmad Brooks looped around the left side of the Saints line and hit quarterback Drew Brees, knocking the ball loose on New Orleans’ second overtime possession. 49ers rookie linebacker Chris Borland covered the fumble at the Saints 17-yard line and coach Jim Harbaugh immediately called for Dawson, who made his 23rd game-winning kick, a knuckler that got little elevation but went through the uprights.

Dawson also kicked 45-yard field goal with 44 seconds left in regulation to tie the game, 24-24.

Brees never saw Brooks coming, and he had other troubles. Despite throwing three touchdown passes — including two in the second half to tight end Jimmy Graham — he was picked off twice in the first half, one of which set up a point-blank touchdown drive for the 49ers.

The loss snapped the Saints’ 11-game home winning streak.

The Saints (4-5) failed to score on their first possession of overtime, and punted the ball back to the 49ers, who took over at their 20. With fresh legs, backup running back Carlos Hyde immediately gashed the Saints for runs of 15 and nine yards, but Saints linebacker Ramon Humber forced a punt with a third-down sack, when defensive coordinator Rob Ryan sent eight defenders in an all-out blitz.

Brees’ fumble came five plays later

Quarterback Colin Kaepernick made an incredibly athletic throw to put the 49ers in position for a tying 45-yard field goal by Dawson in the final minute of regulation. Kaepernick was flushed to the right out of the pocket, but then turned and fired a 51-yard strike across the field to Michael Crabtree, who was wide open behind the Saints secondary.

The 49ers failed to pick up another yard, but Dawson’s field goal made it 24-24 with 44 seconds left.

The Saints had one desperation attempt to win it at the end of regulation, but Graham was called for offensive pass interference in the endzone to negate what would’ve been a game-winning 47-yard walk-off touchdown on a perfectly placed Hail Mary from Brees.

Replays showed Graham pushed off against cornerback Perrish Cox.

Brees made a magical play to get the Saints within 21-17 late in the third quarter. Facing a third-and-6 from the 11, Brees spun away from a blitz by safety Eric Reid and linebacker Michael Wilhoite to find Graham in the end zone, where he beat cornerback Chris Culliver.

Brees played so poorly in the first half (4-of-10 for 53 yards and two interceptions) that he was greeted with boos from the Superdome crowd. Brees’ first interception came on a sideline floater in the first quarter that led to a 19-yard San Francisco touchdown drive. The other came at the end of the half with the Saints in position to close a 21-10 deficit after they had recovered a Kaepernick fumble at the 49ers’ 42.

On second down from the San Francisco 22, Brees threw for Graham up the seam, but the All-Pro tight end was triple covered, and Culliver easily picked off the pass two yards deep in the end zone.

Anquan Boldin shredded the Saints’ secondary in the first half, catching five passes for 86 yards, including a 15-yard grab on a fade pattern in the right corner of the end zone that put San Francisco up 14-0. The 49ers also unleashed their dormant running attack in the first half, with Frank Gore scoring on a 4-yard run and Hyde running in untouched on a 9-yard cutback.

The Saints responded with 10 straight points on a 40-yard field goal by Shayne Graham and a 31-yard pass from Brees to rookie Brandin Cooks, closing the deficit to 14-10, but the 49ers widened the margin to 21-10 with an eight-play, 80-yard drive capped by Boldin’s TD catch.

NOTES: 49ers LB Patrick Willis missed his third consecutive game with a toe injury. … DE Aldon Smith is scheduled to come off a nine-game suspension on Monday. … NT Ian Williams was carted off with a leg injury. … Saints’ CB Keenan Lewis was originally ruled out with a left quad injury, but he returned in the second half. … QB Drew Brees’ 11-yard TD pass to Graham was his 300th as a Saint.