Major national stories in the NFL before, during and after Week 5 captured Tom Brady's return, the Cowboys' surge behind rookie QB Dak Prescott, Odell Beckham Jr. finally catching a touchdown pass and the Falcons' continued ascent.

As for the now lone unbeaten team in the NFL? Ho-hum.

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The Vikings on Sunday submitted another dominating performance with the league's best defense in points allowed (12.6 per game) and turnovers forced (12). Another error-free performance by quarterback Sam Bradford also contributed to an easy win over the Texans.

The lack of national buzz around this non-sexy Vikings team is fine with Mike Zimmer, their outstanding coach, who is more than happy to deflect the attention elsewhere and play the underdog card.

"No one else believes, but I think our team believes," Zimmer told media after the Vikings sacked Panthers quarterback Cam Newton eight times and forced him into three interceptions during their road win over the defending NFC champs in Week 3.

Above all, the Vikings' great start to the season is a reflection of excellent work by Zimmer and general manager Rick Spielman.

After building a contender through all avenues of player acquisition and with solid coaching, they never gave up the ship when analysts and the majority of Vikings fans claimed the team was dead in the water after Teddy Bridgewater was lost for the year eight days before the season opener. Spielman made the gutsy move to trade a first- and (conditional) fourth-round pick to Philadelphia for the oft-injured and generally disappointing Bradford.

I have to to admit — I questioned the price tag, too.

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(Getty Images)

Sam Bradford (Getty Images)

Although I understood the cost to acquire a starting quarterback right before the start of the season, I questioned whether Bradford could play well enough to justify the amount. So far, he has proven Spielman right. But Bradford needs to stay healthy and continue his high level of play.

The Vikings won the NFC North last year, and they were a missed Blair Walsh chip shot from beating the Seahawks in a crushing wild-card round defeat. When Minnesota fell behind Tennessee 10-0 at halftime in this season's opener, many fans had visions of an 0-3 start with Green Bay and Carolina next on the schedule. Then the defense scored two second-half touchdowns against the Titans, and backup QB Shaun Hill efficiently directed the offense to a 25-16 win.

But more concern developed when star running back Adrian Peterson was lost for at least eight weeks with a knee injury suffered against Green Bay, and again when starting left tackle Matt Kalil landed on injured reserve with a hip injury.

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Zimmer wouldn't let injuries derail his team, though. He instead let the defense and Bradford lead the way.

In wins over the Packers, Panthers and Giants, Bradford outplayed Super Bowl QBs Aaron Rodgers, Newton and Eli Manning before the Texans victory. Bradford has made an immediate connection with emerging stars in tight end Kyle Rudolph and wide receiver Stefon Diggs. The quarterback's numbers in his four starts: 70.4 percent completion, six touchdown passes, no turnovers and career-best 109.7 rating.

In the Texans game, the Vikings displayed the depth of talent Spielman and his scouting staff have acquired. With Diggs out nursing a groin injury, undrafted receiver Adam Thielen had a career-best day with seven catches for 127 yards and one touchdown. First-rounder and previous disappointment Cordarrelle Patterson contributed with four receptions for 39 yards and a nice fade route TD. Meanwhile, this year's top pick Laquon Treadwell is riding the bench as he learns the intricacies of coordinator Norv Turner's offense.

Big plays on special teams also have played a major role in the Vikings' success, as Patterson's 61-yard kickoff return helped launch the second half comeback against the Titans. But Marcus Sherels is the biggest special teams star, as he has punt return touchdowns of 54 yards (to aid in the comeback win against the Panthers) and 79 yards (to put the Vikings up 24-0 in the Texans win).

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This Vikings team reminds me of the perennial playoff teams I watched growing up in Minnesota in the late 1960s and early '70s — efficient offense and dominating defense. Those were the years of the Purple People Eaters and a defensive line led by Hall of Famers Alan Page and Carl Eller, along with a leader and iron man in Jim Marshall.

These Vikings have an excellent defensive front seven, led by Pro Bowl defensive end Everson Griffen (four sacks thus far), defensive tackle Linval Joseph and a pair of very productive young linebackers from UCLA, Anthony Barr and Eric Kendricks. But the strength of this defense might lie in Zimmer's schemes. Helping matters is an outstanding secondary led by Pro Bowler Harrison Smith, a modern day version of Steeler great Troy Polamalu, and a bunch of good corners led by perhaps the next great shutdown corner in Xavier Rhodes.

In the Giants game, Rhodes challenged, baited and frustrated Beckham as he held the receiver to a career-worst 23 yards on three catches (on nine targets). This came a week after he and his teammates held Carolina's best receiver, Kelvin Benjamin, without a catch.

Another comparison I'll make: Zimmer reminds me of legendary Vikings coach Bud Grant. Both are great leaders, and both exhibit the qualities of being steadfast — never wavering to the task at hand and being intense on game days while happy to see their teams fly under the radar until playoff time.

Zimmer, however, is a bit more colorful with his quotes, such as this Bill Parcells (his mentor)-like statement after the win over the Giants on Mon

day Night Football: "We still got a long way to go. We're not handing out any medals tonight."

Zimmer and Spielman know there are a few storm clouds on the horizon, beginning with their injury-riddled offensive line having trouble opening holes in the running game (2.5 yards per carry on the season). The addition of veteran tackle Jake Long should help the cause for a group that also has allowed a few too many hits on Bradford, who they can't afford to lose to injury.

Then there's the kicking game, which causes heart palpitations among Vikings fans (and probably teammates and coaches). Walsh followed up the Seattle playoff disaster with two missed field goals and a missed extra point against the Titans. Through five games, he has missed three field goals and two PATs. He was perfect on his lone field goal attempt and four PATs against the Texans, so perhaps he's coming around. But if or when he lines up for a playoff game-winner, everybody in Minnesota will be filled with anxiety.

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The good karma for this Vikings team may lie above all else in Bradford. Perhaps he's a 2016 version of Jim Plunkett, a former first overall draft pick (like Bradford) who struggled through injuries, poor supporting casts and his own inconsistent play with his first two teams (New England and San Francisco) before finally reaching his potential and achieving stardom with the Raiders in directing Super Bowl victories in 1980 and '83.

Similarly, Bradford struggled with the Rams and Eagles before this surprising turn of events in Minnesota. If this season ends with Bradford quarterbacking the Vikings to their first Super Bowl victory, it will be the ultimate response to those who have doubted Bradford and Spielman.

And with a few more wins in the coming weeks, beginning with Bradford's return to Philly after this weekend's bye, the Vikings will be the primary team in the national spotlight, much to Zimmer's chagrin.

Jeff Diamond is the former president of the Titans and the former vice president/general manager of the Vikings. He was selected NFL Executive of the Year in 1998. Diamond is currently a business and sports consultant who also does broadcast and online media work. He is the former chairman and CEO of The Ingram Group. Follow Jeff on Twitter: @jeffdiamondNFL.