SAN FRANCISCO -- Colin Kaepernick was running. He was running so fast Saturday night that his uniform number 7 was unreadable. It was too blurry. And on his 56-yard touchdown sprint in the third quarter, he was moving so fast, one of his tattoos fell off at the 5-yard line. Seemed like it, anyway.

Colin Kaepernick was throwing. He was throwing the ball so well, with such zip and such accuracy, his receivers merely had to stick out their hands and -- thwap! -- the passes would hit their mitts and stick as if they were flies to flypaper.

The 49ers are advancing. They are advancing in the playoffs so impressively after Saturday night's 45-31 victory over the Green Bay Packers that ... well, even the most skeptical pessimist/hater/cynic/naysayer has to begin wondering if a Super Bowl trip really might be in the offing.

And yes, the facts in those first three paragraphs are all interconnected.

The decisive victory sends the 49ers to next Sunday's NFC championship game, to be played either at Atlanta (if the Falcons win their playoff game today) or right back here at Candlestick Park against the Seattle Seahawks. Kickoff will be at noon Pacific time, no matter the location. And if the 49ers win that one, the next kickoff would be in New Orleans with the Vince Lombardi Trophy at stake.

First things first, though: If the question before Saturday night's game was whether second-year quarterback Kaepernick was ready to face postseason pressure in just his eighth NFL start, the answer is a big, fat yes.

Kaepernick's evening began in the worst way possible for any quarterback anywhere: His second pass of the night was picked off by Green Bay cornerback Sam Shields and returned 52-yards for a touchdown to give the Packers a 7-0 lead less than three minutes into the game.

After that, things got better. Much better.

Kaepernick was not exactly perfect the rest of the way -- at one point, he was even flagged for a taunting penalty after spinning the ball in front of a Green Bay defender following a run -- but he unfurled as impressive a postseason performance as any 49er quarterback has ever unfurled.

He rushed for two touchdowns and 181 yards, the most for any NFL quarterback in any game ever. He passed for two touchdowns and 263 yards, completely undressing the Packer secondary in a fashion unseen at Candlestick since the days of (dare we say it?) Steve Young and Joe Montana.

It was quite the achievement for a 25-year-old man who, before the 2012 season began was expected to serve as a backup to starter Alex Smith, who took the 49ers to the NFC title game a year ago. Instead, Smith sustained a concussion in mid-November and Kaepernick took over. He never left the field, even when Smith recovered.

Jim Harbaugh, the 49er head coach, decided to go younger and faster in making Kaepernick his new No. 1 quarterback. It was a big gamble. But there's no doubt now it was the right choice. Because of Kaepernick's reticent nature and his distinctive swagger, fans have wondered what was going on inside his head.

We still don't know, really. But during a pregame interview Saturday with the NFL Network, he was about as candid as he's ever been about what might motivate him.

Kaepernick was asked to name the biggest misperception about his game and said: "That I'm just a running quarterback that is kind of raw. I think there is a huge difference between being a running quarterback and a quarterback that can run. I see that as something as a little disrespectful. And I take that to heart."

Apparently so.

Theoretically, you could say Saturday's result would have been the same with Smith playing quarterback. Smith might have figured out safer ways to win. He would not have tried the risky pass that led to that Packers pick-six. Smith would not have drawn the silly taunting penalty.

At the same time, Smith does not possess the acceleration and speed of Kaepernick, as best demonstrated by that touchdown sprint in the third quarter. After suckering Green Bay linebacker Erik Walden out of position on a read-option play, Kaepernick zoomed around right end into open space and outlegged the Packer defensive backs to the end zone.

Other 49ers carried the ball Saturday. Frank Gore ran for 119 yards on 23 attempts. And there were also other exhilarating runs by Kaepernick -- he finished with 16 carries and an average of 11.3 yards per carry. But that TD dash settled all doubts. He is the offensive proprietor of this team.

And he is going to be open for business again next week.

Contact Mark Purdy at mpurdy@mercurynews.com. Follow him at Twitter.com/mercpurdy.