GLENDALE, Ariz. -- Quick, name the 49ers' most common opponents on "Monday Night Football."
The Dallas Cowboys? Ha, that's happened only twice. The Seattle Seahawks? Only thrice.
When the 49ers (5-2) visit the Arizona Cardinals (4-3) on Monday night, it'll be their sixth meeting on that prime-time stage, and their fifth in the past six seasons.
Only the Rams' franchise and the New York Giants have faced the 49ers more often on "Monday Night Football," doing so eight and seven times, respectively. At some point, the nation might catch on to the 49ers-Cardinals feud.
No, it's not as historic as the Bears-Packers, Cowboys-Redskins or Raiders-Chiefs. It's also not the type of high-stakes rivalry the 49ers have forged with the Cowboys and Giants. But the 49ers and Cardinals aren't friendly neighbors in the increasingly competitive NFC West.
Cardinals defensive end Calais Campbell talked last week how he "really" hates the 49ers "with a passion." The 49ers didn't respond with similar disgust.
"I'm sorry he feels that way," 49ers linebacker Aldon Smith said. "We come out to compete against whoever we play."
Two of the NFL's most competitive defenses will be on display. The 49ers are allowing the second-fewest points per game (14.3), and the Cardinals rank fourth (16.9).
Their matchup lost a bit of pizazz thanks to the Cardinals' three-game losing streak that followed their 4-0 start. But rather than fade quietly,
Asked who would be his primary blocking assignment, 49ers guard Mike Iupati said "Mr. Campbell." Iupati then noted that "talk is cheap" and that the 49ers widely respect the Cardinals organization.
Echoing that stance was 49ers wide receiver Kyle Williams, who trains with Cardinals standout Larry Fitzgerald in the offseason in Arizona. But as much as Williams admires Fitzgerald's work ethic and growing legacy, this is a team sport, and these teams get ornery with each other.
"Anytime you have a division opponent, there's going to be bad blood or the rivalry aspect," Williams said. "Over here in this camp, we're just worried about winning the game and not getting pulled into that (trash talk)."
Such animosity toward the 49ers is nothing new, not after Cardinals defensive tackle Darnell Dockett engaged in a 2010 Twitter war with 49ers tight end Vernon Davis.
Such disdain isn't mandatory, however. "I didn't see that rule over there," said linebacker Clark Haggans, who joined the 49ers almost immediately after his four-year tenure with the Cardinals ended Aug. 31.
Cardinals coach Ken Whisenhunt chalked up the series' intensifying relations to some of their tight outcomes, especially in his first season at the helm in 2007. The 49ers won the season opener 20-17 on "Monday Night Football," then took the rematch 37-31 in overtime in Arizona.
The Cardinals swept the 2008 meetings by scores of 23-13 and 29-24 before the 49ers won the next five encounters, often easily and without allowing more than 16 points in any game.
Just when the 49ers thoughts they extended that streak to six straight wins, the host Cardinals pulled off a second-half comeback and won 21-19 last Dec. 11.
Add it up and it's arguably the NFC West's best rivalry since the Cardinals arrived via 2002 realignment.
"It is? I thought it was us and Seattle," 49ers wide receiver Michael Crabtree said. "I don't really know."
True, the 49ers and Seahawks get after it, but 49ers coach Jim Harbaugh improved to 3-0 against Seahawks nemesis Pete Carroll after a 13-6 win Oct. 18.
Now the 49ers return for a second straight prime-time kickoff. They tout the second-most wins in MNF history with 41. That's only two behind the Dallas Cowboys' mark and, for rivalry's sake, only 35 more than the Cardinals.
"Those guys are definitely where we want to be, those guys are NFC West champs," Cardinals cornerback Patrick Peterson said. "We have a lot to prove, and we want to get where they are."