Linebacker O'Brien Schofield (50) and defensive linemen Darnell Dockett (90) and Dan Williams (92) take down 49ers QB Alex Smith last season in San Francisco.
SAN FRANCISCO – Its genesis is murky, no one real place in which to point.
There is no extended history, since the Cardinals and 49ers didn't get into the same division until 2002. There have been no battles for supremacy, since whenever one team has been playing well enough to be in the mix for the division title, the other has not. There hasn't been a singular moment or polarizing play with which to point.
Clearly, though, in the rivalry between the Cards and Niners, "there is no love lost from either side," Cardinals wide receiver Larry Fitzgerald said. "That's pretty apparent."
No one has been on the front lines of the trash talk more for the Cards than defensive tackle Darnell Dockett, who relishes each matchup with the 49ers – even if he can't put a finger on why it got so heated to begin with.
"They just start talking (expletive)," Dockett said. "They were winning some, and then we started winning, and then people started picking us to win the division, it just was created from there. Then, honestly, I think we played them the best out of anybody in the division, especially on a physical level.
"It's one of those things where they don't like us, we don't like them. There isn't anything to like. They don't respect us, we don't respect them. It's just one of those things."
It's the 49ers with the upper hand right now, both in the standings – at 8-1, they are five games ahead of the 3-6 Cards – and in the series – they've won the last four meetings.
"It's pretty intense although we haven't held up our end of it," Cardinals coach Ken Whisenhunt said.
There have been building blocks for hard feelings. The 49ers, in their last gasp as a good team in 2003 smashed the Cards, 50-14 near the end of the season. The next year, with guys like Fitzgerald and Dockett in their rookie years, the Niners were terrible – yet toppled the Cards by identical 31-28 overtime scores in two games, giving San Francisco their only two wins of the year and costing the Cards a .500 season.
But it was when Whisenhunt arrived in 2007 where the vibe seemed to change. The 49ers, terrible once again, won an overtime game that season at University of Phoenix Stadium that the Cards should have won – kicker Neil Rackers missed a 32-yard field goal.
The next year, the Cardinals felt they were ready to take a step forward and they finally did, sweeping the Niners en route to their first NFC West title, including a dramatic "Monday Night Football" win that included a goal-line stand on the final play of the game.
"My first year, I remember people saying they didn't like the 49ers," said defensive end Calais Campbell, a rookie in 2008. "That was just the way I came into it. It started before I got here. I was born into it."
In 2009, the 49ers thought they were ready to challenge the Cards, and on the field they did, beating the Cardinals twice. But it was the Cards who still won 10 games and fairly easily won the division.
Last year, with the Cards reeling, the Niners dominated both games, even though both sat at the bottom of the division.
"There are a lot of the same players on both sides," said 49ers quarterback Alex Smith, in San Francisco since 2005. "Anytime that happens, you do get a rivalry going."
First-year San Francisco coach Jim Harbaugh hasn't been around it, but "he's done a great job of catching himself up," Smith said.
Harbaugh called the Cardinals "Public enemy number one, two and three" but that had to do more with facing a division opponent as much as any real bitterness with the Cards. Perhaps that will build in time.
For the Cardinals, all division games are also important – but 49ers week is different than playing the Rams or Seahawks.
"This is more of the backyard brawl fight," Dockett said. "It's the motto we have gone by all week: You are either whooping (butt) or getting your (butt) whooped. It's simple.
"The feedback is instant. You are playing against a team that can run the ball well, a team that is 8-1. I'm excited."