SAN FRANCISCO -- Colin Kaepernick played, Alex Smith watched, and at the end of it, nobody in the 49ers locker room could say that the roles should ever be reversed.
In every measurable way, this was a 49ers practical and emotional sea-change, all in a three-hour QB explosion.
With Smith ruled out because of post-concussion symptoms, Kaepernick played incredibly in his first start, dominating the Chicago Bears defense with laser-strike accuracy in the 49ers' 32-7 trouncing at Candlestick Park.
There is no Quarterback Controversy -- because Smith isn't cleared to play yet.
But once he is cleared ...
"We've got two good quarterbacks," running back Frank Gore said. "Lets you know how good our team is."
For Kaepernick, this was a revelatory performance. It was on national TV, against a top team, and it looked easy.
With Kaepernick at the helm -- and Smith on the sideline -- it just looked different than the 49ers offense has looked in years.
Afterward, even the players who have backed Smith the longest and most loyally had to admit that the QB job is a tossup now.
"Alex, he's a genuine guy," said tight end Vernon Davis. "I've been here with him since Day 1 and always supported him.
"Colin, he's the same way -- very humble heart, soft-spoken. He wants to be great. But I can't choose sides.
"I'm here to support either one of them."
That's how fast the NFL can move -- one night, and a QB who led the 49ers to the NFC championship game last January is, at best, on even ground with a second-year QB.
The veteran 49ers are caught in the middle just a bit; they support Smith for everything he has been through and achieved, and now there's the Kaepernick phenomenon.
On Monday, they couldn't deny what they just experienced.
"Colin is the man," Davis said. "I think Colin did a great job. I'm very proud of him. I take my hat off to him, because he did some great things today."
Coach Jim Harbaugh, absolutely Smith's No. 1 backer, officially left the door wide open, either for a straight-up QB competition or for Kaepernick to take over outright.
Harbaugh said his policy is to go with the "hot hand," and helpfully added that both Smith and Kaepernick were hot.
But right now, Kaepernick is scalding -- he completed 16 of 23 pass attempts for 243 yards and two touchdowns, racking up a 133.1 passer rating.
It wasn't just about statistics, either. He looked calm, he threw precisely, and he fired a couple of deep passes that looked as if they were fired out of a missile silo.
The most amazing: a 57-yard perfect strike to Kyle Williams on third-and-7 on the 49ers' second series to set up their first TD.
"That first one he threw to Kyle, you know, that was pretty amazing," tackle Joe Staley said. "Down field, in stride ... I was like, 'Hey, here we go.' "
And what does Staley think about the QB situation between Smith and Kaepernick?
"I think right now we're in a situation where we have two great quarterbacks," Staley said.
"We won tonight with Kaepernick, and we've won a lot of games with Alex, and Alex has played great football for us.
"It's not my spot to make decisions. But I think we're in a great situation right now, because we have two quarterbacks that we can play great football with."
Just listen to Davis talk about one play -- a zip pass from Kaepernick in the fourth quarter between the defense.
After the play, Davis ran over to Kaepernick, then put his hands together and bowed to his QB.
"I was just so proud of him at that moment, because the ball that he threw me, it was one of those balls that you see Tom Brady throw," Davis said.
"Second window, right on the money, wow, surprise. I didn't expect the ball to come, because we've run that play quite a few times, and the tight end usually doesn't get the ball on that play."
Meanwhile, Smith wore a red sweat jacket and stood mostly quiet on the sideline.
He encouraged Kaepernick at times and huddled with other players occasionally, flipping through binders like an assistant coach.
"He was just telling me to trust what I was seeing," Kaepernick said of Smith. "He thought I was seeing the field well."
That was not in doubt. Who could say anything else? This might not be a full-fledged Quarterback Controversy, and it might never really be.
Because if Kaepernick keeps playing like this, there is no controversy. He might not, but with one full game under his belt, the evidence is heavily in his favor.
The players could feel that. They were there. They knew things had changed, in a three-hour flash.
The QB job is up for grabs, and Colin Kaepernick probably can leap higher than anybody right now.