SAN FRANCISCO -- "The Cowboy" not only saddled up and went the distance Saturday but also had a pretty fair evening of ridin' and ropin'.

Justin Smith, wearing a cumbersome brace on his left arm to protect a partially torn triceps muscle, nonetheless restored fire and formidability to the 49ers defense by playing virtually every down against the Green Bay Packers.

While statistics don't do justice to what Smith does on the field, he was credited with five tackles in the 49ers' 45-31 romp, four of them unassisted. He drew the usual double-teams and pretty much looked like his old terrorizing self.

"It was what it was, and it felt a hell of a lot better than I thought it was going to feel," Smith said. "Now I just have to keep on going."

"From my eye, he looked stout against the run," coach Jim Harbaugh said. "The legend grows."

The 12-year veteran lineman had a painkilling injection that helped him get through four quarters.

"I'll get some X-rays tomorrow to make sure it didn't move too much, and we'll go from there," Smith said. "(The brace) worked pretty good, but I had some stuff in there, so I didn't really feel it a whole lot."

Smith said he didn't feel limited and wasn't concerned about whether he could play the entire game.

"I tried not to think about it, to be honest with you," he said. "I tried to be as normal about it as I could, and in the end, it held up. I was real happy to go the distance, but I didn't really have any thoughts about it one way or the other.

"You can't be worrying about stuff out there, or you'll get whupped pretty good."

One person who watched Smith closely was Ricky Jean Francois, who had replaced Smith for the last 21/2 games of the regular season. Jean Francois was used for only a few plays, when Smith needed a breather.

"He played like himself, getting pressure, directing stunts here and there, getting traffic right," Jean Francois said. "I was never worried about him. Once I saw him work out in practice, there were no worries. I know a lot of people focused on it, but he was back to being 'The Cowboy.' "

Linebacker Aldon Smith, whose pass-rushing effectiveness was impacted by Justin Smith's absence, wasn't worried, either.

"From the time he came back to practice, it was good vibes all around," said the younger Smith. "I know Justin, and I know what he's capable of. He wouldn't be out there if he felt he'd be hurting the team, so I knew he'd play well."

After returning to action, Justin Smith doesn't envision a setback with the 49ers headed to the NFC Championship game for a second straight year.

"I'm just glad to have a chance to play in it again and have an opportunity to go to the Super Bowl," Smith said. "I've played 12 years, so I know how hard it is to get this far."