NEW ORLEANS — Ahmad Brooks, Donte Whitner and the rest of the San Francisco defense made enough plays for the 49ers to win no matter who they started at quarterback.
Brooks and Whitner returned interceptions for touchdowns, the 49ers sacked Drew Brees five times, and San Francisco ended the Saints' three-game winning streak, 31-21 on Sunday.
"We always want to be the best defense on the field, especially on the road," Whitner said. "When you play us, you are going to get hit. That's our identity: smart, hard-nose, physical football."
Quarterback Colin Kaepernick was solid in his second career start while Alex Smith, healthy enough to suit up after recovering from a concussion, watched from the sideline. Kaepernick passed for 231 yards, including a short touchdown to Frank Gore, and ran for a 7-yard score. His first career interception was inconsequential.
Coach Jim Harbaugh implied that starting Kaepernick had more to do with preserving Smith's long-term health than on performance, but he was noncommittal about who might start next week at St. Louis.
"The fact (Smith) had symptoms seven to eight days later, I'm not going to put a guy back out there," Harbaugh said.
Smith said he wants to start, "but it's not my decision.''
Brees finished with 267 yards and three touchdowns. After rushing for 140 yards or more in each of its previous three games, New Orleans had 59 yards.
Marques Colston set a Saints record with his 56th career touchdown with the club.
The Niners rushed for 144 yards, led by Gore with 83. The Saints shut down tight end Vernon Davis, but the Niners' other tight end, Delanie Walker, had three catches for 81 yards, a 45-yarder setting up a touchdown.
San Francisco's interceptions turned a 14-7 deficit into a 28-14 lead. Brooks returned the first one 50 yards late in the first half. The second came on Brees' first pass of the second half. The ball deflected off Colston's hands as the leaping receiver was upended. Whitner snagged the deflected pass and returned it 42 yards to make it 28-14. "Obviously, what was glaring were the two turnovers that resulted in touchdowns for them," Brees said.