The two teams don't like each other much and have become fierce rivals since they were put in the NFC West in the 2002 NFL realignment.
In order to understand why the Cardinals hate the 49ers and why San Francisco has reason to hate Arizona right back, let's go back to when the Cardinals first came to Arizona in 1988.
The Cardinals happened to play San Francisco that season and the game had a bizarre ending. San Francisco was looking to make Arizona another notch in the win column and led 23-0 in the third quarter.
The Cardinals, however, pulled off an improbable rally to win 24-23, scoring a touchdown with three seconds left in regulation with Al Del Greco's extra point won the game. It made for a dramatic final six seconds of the game.
A shocking rally is one thing, but a career-ending hit is another. San Francisco fans were stunned when Arizona cornerback Aeneas Williams came untouched on a cornerback blitz and leveled 49ers quarterback Steve Young, who suffered a concussion and was subsequently forced to retire after the 1999 season.
Safe to say that 49er fans still sting over Young's career ending on that play.
When the two teams started to meet twice a season, the heat was turned up even more.
In 2004, San Francisco had a miserable 2-14 season, but both of their wins were 31-28 overtime triumphs against the Cardinals.
Arizona lost with Tim Rattay at quarterback and again with Ken Dorsey taking the snaps. From 2003-06, both teams were the at the bottom of the division as they went through many similar struggles year after year.
San Francisco has won seven of its last eight meetings with Arizona, which has only made fans' blood boil that much hotter when the 49ers are next on the schedule.
Former Arizona coach Ken Whisenhunt said the bad feelings already existed when he arrived in Arizona in 2007, according to the Arizona Republic. Whisenhunt also drew a parallel to some of the AFC North battles he had been a part of while coaching with the Steelers:
This division has become a lot like that division, a physical smash-mouth type defensive division. These division games become brawls.
The rivalry was amped up with a goal-line stand in 2008 that swung the game to Arizona. It could also have been fueled by the hit Adrian Wilson put on San Francisco tight end Vernon Davis, resulting in a $10,000 fine for Wilson.
There was also a war of words on Twitter between Davis and Arizona defensive lineman Darnell Dockett.
In 2011, Arizona wide receiver Early Doucet got into it with 49ers safety Dashon Golson and the two mixed it up. Watch the bottom of the screen as the clip starts.
The word "hate" gets thrown into this rivalry as well.
Former Arizona running back Beanie Wells hated the 49ers, as noted by Pro Football Talk. Teammate Calais Campbell hates the 49ers with a passion as well, though former San Francisco quarterback Alex Smith shrugged it off.
There's no doubt that both teams have an intense rivalry and history shows there's plenty of fuel for the proverbial fire.
It may take a little time for the rivalry to renew itself to such high levels again with Arizona having a new coach in Bruce Arians. Jim Harbaugh, freakouts and all, is coming off of a loss in the Super Bowl and San Francisco wants to get back to the big game to finish what it didn't achieve last season.
So, what can a Cardinals fan do to express the hatred that seems to run between these teams and their fans? Since they really can't point to any noteworthy on-field results, it's easy for Arizona fans to go after San Francisco players and the city itself.
In Arizona, they can start getting on 49er players like quarterback Colin Kaepernick, who made waves this offseason for wearing a Dolphins hat. The LA Times showed Kaepernick wearing the hat. He then "corrected" it a couple days later with another posting on Instagram, per NLF.com
Kaepernick also bared all for ESPN's Body Issue. Kaepernick can get ribbed for having most of his upper body covered in tattoos. It's one thing to have some ink. It's another to look like a pen factory exploded all over your body.
Arizona fans can fall back on classics like calling the Niners the "San Francisco Whiners", but those get old quickly and there are a plethora of jokes out there about the Cardinals as well, most of which couldn't be printed here.
The Cardinals visit San Francisco Oct. 13 this season in a Week 6 matchup. After that, the venom will have plenty of time to build back up before their Week 17 finale rematch in Phoenix.