If there were any doubts over whether the San Francisco 49ers were legitimate challengers in the National Football Conference (NFC), they answered them in resounding fashion with their victory over the previously unbeaten Detroit Lions on Sunday.
Now the question is just how far Jim Harbaugh's team can go?
San Francisco are 5-1, the number two seed in the NFC behind the unbeaten defending Super Bowl champions, the Green Bay Packers, and they have a 2.5 game lead in the NFC West.
The 49ers have come from behind to win three straight road games -- in Cincinnati, Philadelphia and Detroit.
Before this season, pundits questioned whether their quarterback Alex Smith, in his seventh year, was ever going to be the right man for the job.
However, few are asking that now after the way he led his team to a game-winning touchdown at noisy Ford Field.
I've never been a part of something like this, especially since I have been a pro, Smith said after Sunday's win.
It is all in marked contrast to last year's 0-5 start under then coach Mike Singletary, their worst start since 1979.
The 6-10 finish to the season, after Singletary was fired with just a game remaining, was a major under-achievement for a team widely viewed as having plenty of talent.
It is not only Smith who has undergone a transformation under Harbaugh, who joined the 49ers after a successful spell as head coach at Stanford University.
LOCKER ROOM COMMITMENT
The locker room is what jumps out at me. Just so different -- the commitment level, the sacrifice, guys are just different and it is fun to be a part of. They just don't quit and it shows up on game day, said Smith.
Harbaugh hit the headlines for being involved in a post-game handshake incident with his opposite number, Lions head coach Jim Schwartz. While the NFL ruled on Monday there was no need for a fine, the incident highlighted the rookie coach's passion.
That emotion was on display in footage of the 49ers locker-room after the game where Harbaugh made an impassioned speech in which he praised the best defensive performance I have ever seen.
After the game he had said: To see your guys go out and perform that way, yeah, you do get emotional. It fires me up, it fires me up a lot. I'm not going to apologize for that.
Smith certainly did not feel the need for apologies from his coach, saying: This team loves and appreciates the fact that our coach is fiery and a competitor. We like that.
While there is an all-round solidity to the 49ers, it is their defense which is making the strongest impression -- linebacker Patrick Willis produced three pass break-ups against Detroit to continue his excellent season.
The 49ers are second in the league in rushing defense and they also showed they can get after the quarterback -- Aldon Smith came with two sacks on Detroit quarterback Matthew Stafford.
The secondary ensured that Lions receiver Calvin Johnson, who had nine touchdowns in five games, did not make a score.
On the offensive side, running back Frank Gore is currently the fifth most productive player in rushing yards -- he has made 541 yards in five starts and exceeded 100 yards in each of his last three games, scoring a touchdown in each one.
For Harbaugh, though, defeating the Lions in Detroit was above all about character and the melding together of the component parts into an effective collective.
I really felt that our team came together through adversity. They were tough conditions to play in, but they hung together and they found a way to win, he said.