Rapid Reaction: 49ers 31, Saints 21

NEW ORLEANS -- Thoughts on the San Francisco 49ers' 31-21 victory over the New Orleans Saints at the Superdome in Week 12:

What it means: The 49ers improved to 8-2-1, tightening their lead over Seattle (6-5) for first place in the NFC West. They proved they could beat a hot team in a hostile environment with a second-year quarterback, Colin Kaepernick, making his second career start. Big plays from the San Francisco defense made it happen. Quarterback drama will continue to dominate headlines for the 49ers, but their defense deserves attention.

What I liked: Kaepernick completed all four pass attempts in the first quarter, capping the 49ers' opening drive with a touchdown run. He opened the third quarter by leading another scoring drive, this one featuring a 45-yard pass to Delanie Walker on third-and-2. Kaepernick finished that drive with a 6-yard scoring pass to Frank Gore.

The 49ers' defense provided two touchdowns on interception returns, offsetting the Saints' biggest strength, quarterback Drew Brees. Ahmad Brooks returned one right before halftime, bailing out Kaepernick from the interception Kaepernick threw. Donte Whitner returned the other one to give San Francisco needed breathing room in the second half. That one took the pressure off Kaepernick.

The 49ers were the more physical team and it showed as the game progressed, both in the way they ran the ball and in the way they put hard hits on the Saints' receivers. Dashon Goldson, Whitner and others 49ers defenders delivered punishing shots. Saints players were repeatedly slow to get up. The NFL is a quarterback-dominated league, but the 49ers dominated one of the best quarterbacks around.

Left tackle Joe Staley drove Saints linebacker Jonathan Vilma well down the field in clearing the way for Kendall Hunter's 21-yard run to set up a touchdown. Fullback Bruce Miller also stood out with a couple of strong blocks and for his efforts as a receiver.

What I didn't like: Ted Ginn Jr. muffed a punt midway through the second quarter, setting up the Saints for a quick touchdown to break a 7-7 tie. Ginn arguably should not have fielded the ball in that situation. Ginn has been very reliable as a returner for the 49ers. This one hurt. The 49ers replaced him with Kyle Williams, but Williams left the game with an injury.

The 49ers had success with linebacker blitzes. San Francisco generally relies on its four-man rushes to get pressure, but the blitzes became effective, particularly after the Saints fell behind. Brees frequently had to settle for throwing away the ball or dumping it off.

San Francisco burned a timeout early, suffered a delay penalty on third down and had too many penalties overall. Gore and Vernon Davis dropped passes. Michael Crabtree also should have caught a ball Kaepernick threaded to him on third down. Kaepernick, meanwhile, seemed to rush his throw on the ball New Orleans picked off. The snap was low, possibly throwing off the play.

Injury watch: The 49ers lost Hunter and receiver Kyle Williams to injuries on the same play with 52 seconds left in the third quarter.

QB stat line: Kaepernick completed 16 of 25 passes (64 percent) for 231 yards with one passing touchdown, one rushing touchdown, no sacks, one interception and a 90.6 NFL passer rating. Brees completed 23 of 36 passes (64 percent) for 215 yards with three touchdowns, two interceptions, five sacks and an 84.8 passer rating.

What's next: The 49ers visit the St. Louis Rams in Week 13.