The Tennessee Titans were allowing a league-high 61.9% of third downs to be converted when they welcomed into Nissan Stadium a meek Chicago Bears offense that was converting 34.9% of its third downs to rank next to dead last.

So what happened when very little push came to utter lack of shove on football's most critical down?

Naturally, the Bears offense proved that its futility cannot be overestimated. It is a true lack of force to not be reckoned with heading into next Monday night's game against the Vikings at Soldier Field.

Yes, Chicago converted two of 15 third downs at Tennessee. That's 13.3%, which must have ticked off 100% of a Bears defense that saw another gem wasted.

The Titans won with 228 yards and 11 first downs. They won with Ryan Tannehill completing 10 passes. They won with Derrick Henry being held to 68 yards on 21 carries. They won with 20 of those carries netting 42 yards.

They won because Chicago's offense is B-R-U-T-A-L. They won because Nick Foles — that streaky Vikings killer from the NFC title game in January 2018 — threw 14 third-down passes with 12 failed conversions.

But it's not just Foles. Or Mitch Trubisky before him.

"There's not just one person right now with this offense," said 2018 NFL Coach of the Year Matt Nagy, whose seat is getting a tad warm in today's what-have-you-done-for-me-right-now league.

"There's a lot of different things. There's a multitude of issues that we're having. Where you get a little frustrated is if there's 10 guys that are doing something the right way and there's one guy that's not, that's where we've got to get that unison back of understanding the effectiveness of a play.

"Or just stay within the play sometimes. I think that's very valuable regardless of No. 1, who the quarterback is, and regardless of No. 2, who the O-line is."

Right now, the 3-5 Vikings are celebrating a two-game winning streak and the jelling of an offensive line that has had the same five starters for the past three games. Meanwhile, the 5-4 Bears are stuck in a three-game losing streak that's seen them start three different offensive line combinations.

Center Cody Whitehair has missed the past two games because of a calf injury and COVID-19 protocol. Right tackle Bobby Massie is out for at least a month with a knee sprain. And left guard James Daniels is out for the season with a torn pectoral muscle.

If that wasn't bad enough, Chicago also had two key backup linemen — Sam Mustipher and Jason Spriggs — miss the Tennessee game because of COVID-19 protocol. That resulted in center Alex Bars and left guard Arlington Hambright making their first NFL starts, and the team's worst offensive line starter, Rashaad Coward, moving from left guard to right tackle.

The shuffling up front led to some classic comedy of errors, Chicago style.

Trailing 10-0 late in the first half, Chicago forced a three-and-out to give the offense the ball at the Tennessee 48.

"We force them to punt from their 2-yard line," said Nagy, "And we go penalty, penalty."

The drive started with left tackle Charles Leno false-starting.

First-and-15 from the Chicago 47.

Then Coward was flagged for illegal use of hands.

First-and-25 from the Chicago 37. Bye-bye scoring opportunity.

"That can't happen," said Nagy, "but it did."

And there's more.

In the second half, Nagy decided to go for it on fourth-and-1 at the Tennessee 31.

False start, Hambright.

Nagy then decided to go for it on fourth-and-6.

False start, tight end Jimmy Graham.

Nagy then decided to punt.

In other words, yes, the Vikings are 2-10 in their last 12 trips to Chicago. Yes, they play particularly awful there in prime time.

But there's a reason the Vikings and Dalvin Cook are favored by 2½ points.

They should outscore the Bears and take a 4-5 record into a three-game homestand against 2-7 Dallas, 3-6 Carolina and 1-7 Jacksonville.

And that, folks, is why you don't tank seasons, even when you start 1-5.

Mark Craig is an NFL and Vikings Insider. Twitter: @markcraigNFL. E-mail: mcraig@startribune.com