And they did it with an unforgettable performance by QB Alex Smith, a player whose well-documented career peaks and valleys would usually result in journeyman status.
But over the course of seven offensive coordinators, losing seasons, a missed 2008 with injury and his 2011 breakout, Smith has remained in scarlet and gold.
Despite career highs in yards (3,144), completions (273), completion percentage (61.3), and QB rating (90.7) in 2011, Smith was labeled a "game manager" early on. He was counted on to not turn the ball over, but he also wasn't expected to come up with big yardage or clutch plays.
No one can deny San Francisco's reliance on defense and special teams all season, but it's this very dominance in other areas that allowed Smith to shine against the Saints.
Jim Harbaugh picked a good time to unleash Smith, who finished the game with season highs of 24 completions, 299 yards and three touchdowns through the air.
With the 49ers down 24-23 and just over two minutes remaining, Smith came up with an incredible 28-yard touchdown run to take the lead.
The Saints scored on their ensuing possession to take the lead back, and all eyes shifted again to the No. 1 overall pick from 2005 to see what he could come up with. Game managers aren't supposed to have answers with 1:12 remaining in their first ever playoff game while losing by three.
In anything but game manager fashion, Smith led his team 85 yards down the field, aided by a 47-yard pass play to Vernon Davis. The comeback was completed on a 14-yard touchdown throw, again to Davis, with just nine seconds remaining.
The play will certainly go down as one of the best in a long line of historic 49ers playoff moments, notably alongside Dwight Clark's catch in the 1981 NFC Championship and Terrell Owens's catch in the 1998 Wild Card.
Smith has certainly set his bar higher than it was before Saturday's game, and his performance against the Saints should convince us all that he'll be ready for the challenge.