The 1972 Miami Dolphins need not worry about having their 40th anniversary celebration of the NFL’s only perfect season disrupted by party-crashers.

Three weeks into the 2012 campaign, just three teams remain undefeated – Houston, Atlanta and Arizona. San Francisco, which entered Sunday’s games perceived as the NFL’s top franchise, suffered its first loss at Minnesota. San Diego and Philadelphia also fell by the wayside against the Falcons and Cardinalsrespectively.

History shows the Texans, Falcons and Cardinals are headed toward postseason berths. Roughly 76 percent of the teams that have opened 3-0 since 1990 reached the playoffs.

But finishing undefeated like Don Shula’s ballyhooed squad? Let’s not get carried away.

The 1972 Dolphins won’t have to keep the champagne on ice much longer. Here’s a look at what the Cardinals, Falcons and Texans have done well so far – and the most likely place in the schedule where they will finally slip.

HOUSTON

What’s gone right? NFL Defensive Player of the Year candidate J.J. Watt leads a smothering unit. The second-year defensive end terrorized Denver quarterback Peyton Manning for 1.5 sacks in Sunday’s 31-25 road victory and now has 4.5 on the season. The Texans also field one of the NFL’s most balanced offenses.

Biggest flaw: The right side of the offensive line still hasn’t come together since the offseason departures of guard Mike Brisiel (Oakland) and tackle Eric Winston (Kansas City).

First loss: Barring an upset against visiting Tennessee or the host New York Jets in the next two games, expect Houston to fall during a brutal back-to-back stretch in Weeks 6 and 7. Although the Texans will be playing at home, defeating Green Bay on a Monday night and Baltimore six days later is too tall a task.

ATLANTA

What’s gone right? Falcons quarterback Matt Ryan has never looked better in his fifth NFL season thanks to the emergence of second-year wide receiver Julio Jones to complement other top targets Roddy White and Tony Gonzalez. Defensively, the diverse looks being deployed by new coordinator Mike Nolan have given the opposition fits.

Biggest flaw: While the secondary has played well – especially safeties Thomas DeCoud and William Moore– the Week 1 loss of Brent Grimes to a season-ending Achilles tendon injury could bite the Falcons if another cornerback goes down.

First loss: Provided quarterback Cam Newton has stopped sulking, Carolina in Week 4 is a consideration with the Panthers having three extra days to prepare for the Sept. 30 matchup at the Georgia Dome. If the Falcons get past Carolina, the next likely stumbling block would be an Oct. 28 road game against Philadelphia in Week 8. It should be noted, though, that Atlanta is off to a 2-0 road start for the first time since Mike Smith became head coach in 2008. The Falcons were a combined 1-7 in their first two road games the previous four seasons.

ARIZONA

What’s gone right? Is the NFL ready for a head coach with dreadlocks? With the way Arizona’s defense has dominated, coordinator Ray Horton should be running his own team in 2013. Kevin Kolb also deserves props for rebounding from a dreadful preseason after starting quarterback John Skeltonwent down with a sprained ankle in Week 1 against Seattle.

Biggest flaw: The Kolb-led offense reminds no one of the Halcyon days of Kurt Warner.

First loss: Arizona should be favored against their next four opponents – Miami, St. Louis, Buffalo and Minnesota. If they survive that stretch, the Cardinals would be 7-0 entering a Monday Night Football showdown Oct. 28 against NFC West rival San Francisco. After a bye, the Cardinals play at Green Bay on November 4. Good luck.

And now, a look at the entire Week 3 slate of Sunday games:

Jacksonville 22, Indianapolis 17: The Jaguars signed free agent Laurent Robinson to a five-year, $33 million contract and gave Justin Blackmon a four-year, $18.5 million deal as the No. 5 overall pick in April’s draft. The wide receiver who caught the game-winning 80-yard touchdown pass Sunday with 45 seconds remaining?Cecil Shorts III – a 2011 fourth-round pick from the University of Mount Union with a base salary of less than $500,000 this season. Speaking of paydays, Jags running back Maurice Jones-Drew expressed unhappiness with his contract status by holding out during the preseason. His 177-yard, one-touchdown rushing performance sent a more powerful statement about worthiness for a new deal.

Kansas City 27, New Orleans 24: The Saints’ ongoing 2012 troubles will generate the biggest post-game headlines, but the Chiefs deserve credit for finally showing some life after 10 quarters of uninspiring football. Jamaal Charles (233 rushing yards) proved he’s back from the serious knee injury that landed him on injured reserve in 2011 while the defense held New Orleans to just 70 second-half yards. The Saints will now try to become only the second club to qualify for the playoffs after an 0-3 start since the NFL adopted a 12-team format in 1990. The 1993 San Diego Chargersopened the season 0-4 – which is the same record New Orleans is expected to have after its next game in Green Bay.

Cincinnati 38, Washington 31: The Bengals have flaws along an offensive line that has allowed too many sacks (12) and in an injury-riddled secondary. But the second and third wide receiver positions that were considered the biggest question mark entering the season have become a strength. Rookie Mohamed Sanu threw a 73-yard touchdown pass on the game’s opening play while Armon Binns and Andrew Hawkins later scored on long throws from quarterback Andy Dalton. Some of those opportunities are being created by the attention given to Bengals wideoutA.J. Green, who finished with nine catches for 183 yards against a Redskins defense reeling because of injuries.

Chicago 23, St. Louis 6: Just like in a 23-10 loss to Green Bay, the Bears struggled to find consistency on offense. But that didn’t matter Sunday against a Rams unit that has even more problems. St. Louis never even reached Chicago’s red-zone. The Bears’ defensive line registered five sacks and stuffed Steven Jackson (11 attempts for 29 yards) in the running game. CornerbackTim Jennings also continued his push for a Pro Bowl berth with his fourth interception. The last time St. Louis had a winning record was Week 8 of the 2006 season.

Dallas 16, Tampa Bay 10: Bucs head coach Greg Schiano remains defiant about his assaults on game-ending victory formations. Unfortunately for him, Tampa Bay’s offense didn’t put up the same fight when a win was in reach. Dallas also deserves credit for limiting Bucs quarterback Josh Freeman to 10-of-28 passing for 110 yards with one touchdown and one interception. A yeoman’s effort was needed because of a Cowboys offense that committed six pre-snap penalties, three turnovers and provided shoddy protection of quarterback Tony Romo. Tampa Bay may have lost its top pass rusher when defensive end Adrian Clayborn suffered a knee injury. Just a thought: If the Bucs think they have a legitimate playoff shot, would they approach Indianapolis about a trade for Dwight Freeney if Clayborn is out?

Minnesota 24, San Francisco 13: The maulers became the maulees. Minnesota was the more physical team, which is far from the norm for the 49ers under head coach Jim Harbaugh. Not only is Christian Ponder developing nicely, but the second-year quarterback will regain the services of Jerome Simpson now that the fleet wide receiver has finished a three-game drug suspension. A three-catch, 17-yard performance in his latest homecoming to Minnesota shows 49ers wide receiver Randy Moss may not have much left in the tank. However, wide receiver Michael Crabtree has developed an outstanding third-down rapport with quarterback Alex Smith.

Tennessee 44, Detroit 41: This game could be played a zillion times without producing the same number of wild plays that made Tennessee the first team in NFL history to score five touchdowns of 60-plus yards, including a reprise of the Music City Miracle special-teams play from the 1999 season. Titans running back Chris Johnson remains a shell of his 2009-2010 self. It’s disappointing that a team leader like Lions center Dominic Raiola wouldn’t address the media after miscommunication on a fourth-down snap with backup quarterback Shaun Hill in overtime cost Detroit the game. Fresh off a two-game drug suspension, Lions running back Mikel Leshoure had a 100-yard outing in his NFL debut. It’s no coincidence that wide receiver Calvin Johnson (10 catches for 164 yards and one touchdown) had his best outing of the season with Tennessee forced to respect the rushing game.

Buffalo 24, Cleveland 14: The Browns extended the NFL’s longest losing streak to nine games largely because of poor defense. Injuries continue to hit Buffalo skill-position players with dynamic running back C.J. Spiller(shoulder) the latest on the sideline. The key to this Billsvictory was a defensive line that stuffed running backTrent Richardson (12 carries for 27 yards) and punished quarterback Brandon Weeden (sacked four times and intercepted twice in the final five minutes).

New York Jets 23, Miami 20: Somewhere, Jets offensive coordinator Tony Sparano is enjoying a reverse fist-pump. Known for his exaggerated celebrations following field goals when Dolphins head coach, Sparano watched from the other sideline as Dan Carpentermissed the kick that would have given Miami the lead in overtime. Another Dolphins special-teams gaffe occurred when head coach Joe Philbin called a timeout just before Nick Folk was set to attempt the game-winning 33-yard field goal. Miami blocked the kick after that whistle blew but couldn’t repeat the trick on the subsequent do-over. While the Jets should be encouraged by the resiliency of quarterback Mark Sanchez and wide receiver Santonio Holmes, any happiness from the win is tempered by the possibility that star cornerback Darrelle Revis suffered a season-ending knee injury.

Atlanta 27, San Diego 3: It sounds like a recipe for disaster. The Falcons were traveling to the West Coast on a short week after an emotional Monday night victory over Denver and the letdown that immediately followed when running back Michael Turner was arrested on a DUI charge afterward. It was the Chargers, though, who played like they were in a fog. Running back Ryan Mathews fumbled for the 11th time in his 27th career NFL game and left tackle Mike Harris was overmatched against pass-rushers John Abraham and Kroy Biermann. Philip Rivers didn’t help matters with subpar quarterbacking as counterpart Matt Ryan picked apart San Diego’s defense.

Arizona 27, Philadelphia 6: This loss reaffirmed it’s only a matter of time before Eaglesquarterback Michael Vick gets sidelined by injury. Blame an offensive line afflicted by injuries as well as Vick inviting hits by being too slow getting rid of the football. Twelve turnovers in three games were too much for Philadelphia to overcome for a 3-0 start. I admit to believing Arizona’s Russ Grimm was an overrated offensive line coach, but the performance of his unit the past three weeks has proven me wrong. The once-unthinkable happened to Eagles cornerback Nnamdi Asomugha when he was beaten for a touchdown pass in the second straight game. Welcome back to the NFL, Larry Fitzgerald, with a season-high nine catches for 114 yards and a score.

Oakland 34, Pittsburgh 31: Remember last season when it seemed destined that the Raiderswould win the day after team owner and NFL icon Al Davis passed away? I got that same vibe Sunday after ex-Raiders running back Marcus Allen lit the Al Davis flame, officially ending the feud that had developed between the two Hall of Famers. The Raiders overcame a 10-point deficit Sunday and kept their composure despite the scary injury suffered by wide receiver Darrius Heyward-Bey on an illegal hit by Steelers safety Ryan Mundy that the scab, err, replacement officials missed. Carson Palmer and Darren McFadden enjoyed their best performances of the season against a Steelers defense that struggled without injured free safety Troy Polamalu and outside linebacker James Harrison.

Houston 31, Denver 25: Something to consider: The Texans spent far more time preparing to face Peyton Manning when he was with Indianapolis than Broncos teammates have with their new starting quarterback. That was reflected with how well Houston played while opening a 31-11 lead. Big plays made by Kevin Walter (52-yard touchdown reception) and Lestar Jean (46-yard catch) are encouraging with the Texans having long-sought complements to No. 1 wide receiver Andre Johnson. After enjoying much better second-half performances in all three games, the Broncos must get out of the blocks quicker to win on a consistent basis.

Baltimore 31, New England 30: After raising eyebrows with his minimizing of Wes Welker in the first two games, Patriots offensive coordinator Josh McDaniels successfully reincorporated the wide receiver into the attack with tight end Aaron Hernandez (ankle) now sidelined. Welker (eight catches for 142 yards) and Brandon Lloyd (9-108) both ran wild against a secondary that didn’t receive enough support from the front seven. No matter. The Ravens and wide receiver Torrey Smith paid fitting tribute to his 19-year-old brother who died early Sunday morning in a motorcycle crash. Smith finished with six catches for 127 yards and two touchdowns as the Ravens overcame a double-deficit.