PHILADELPHIA – The Philly cheesesteak is a glorious mess of grilled meat slathered with peppers, onions and provolone on what East Coasters call a "hoagie" roll.

When visiting Philadelphia, one must remember to wipe off the grease cascading from this famous delicacy before shaking hands or, say, playing in a football game.

Thursday night at Lincoln Financial Field, the Vikings played as if they forgot their wet wipes, not to mention their football sense. They lost four fumbles and the game, 34-28. They even had a fifth lost fumble nullified by a defensive penalty.

Other than turnovers, the Vikings have only three problems:

Their offensive line, their defensive line, and the through-line connecting their last three losses.

"You know, we did a lot of good things," linebacker Jordan Hicks said. "Second week saying that — we did a lot of good things, but there's some obvious things that we have to clean up."

For the first time in coach Kevin O'Connell's tenure, he is dealing with a losing streak.

For the first time, he has lost consecutive regular-season games. Add in last year's playoff loss, and he has lost three games in a row to teams with physical defensive fronts that overwhelmed the Vikings offensive line.

In 2022, the Vikings' loss at Philadelphia on Thursday night in Week 2 quickly became an aberration. They began the O'Connell Era with eight victories in their first nine games, and a loss to the talented Eagles in their den of iniquity was hardly a major blemish on his résumé.

In 2023, a Week 2 visit to the Linc, following a disappointing opening-week loss to Tampa Bay at home, felt more ominous.

The Vikings are now 5-6 since that epic victory at Buffalo last November. O'Connell's only victory in his past five games was against the not-even-trying Bears in last year's finale.

Thursday, the Vikings found themselves without starting center Garrett Bradbury and left tackle Christian Darrisaw, both missing because of injuries.

That meant the Vikings had to employ this starting line: Outstanding right tackle Brian O'Neill, struggling second-year guard Ed Ingram, backup center Austin Schlottmann, workmanlike guard Ezra Cleveland, and backup tackle Oli Udoh.

Udoh gave up the sack that forced Kirk Cousins to fumble. Early in the fourth quarter, he was injured and replaced by David Quessenberry.

The Eagles defensive tackles — star Fletcher Cox, the improving Jordan Davis and first-round draft pick Jalen Carter — shredded the middle of that line in the early going.

The Vikings countered in the second quarter with an up-tempo offense that limited Philadelphia's ability to substitute fresh defensive linemen. That strategy allowed the Vikings to produce a nine-play, 55-yard touchdown drive that ended with a short pass to tight end T.J. Hockenson. It was a deft piece of coaching, and proof that Hockenson deserves a medal of honor for recovering so quickly from the grievous injuries that limited him during training camp.

(Or, perhaps, he was holding out, or "holding in," and he really didn't have an ear infection and sore back. Just a guess.)

The Eagles countered with their own deft offensive coaching. Vikings defensive coordinator Brian Flores began the next drive with one true interior defensive lineman, Harrison Phillips, on the field, along with five linebackers, two cornerbacks and three safeties.

Philadelphia coach Nick Sirianni attacked the Vikings line with a series of interior runs, and the Eagles pieced together an old-school, 16-play, 75-yard touchdown drive that ended with quarterback Jalen Hurts lunging through the middle of the Vikings line for a 1-yard touchdown.

It was 10-7, and the Eagles were on their way to rushing for 259 yards, the kind of total you usually see when Alabama plays Louisiana Southeastern Tech.

By the end of the first half, the Vikings had lost fumbles by running back Alexander Mattison, punt returner Brandon Powell and star receiver Justin Jefferson, who, with 29 seconds remaining in the first half, lost the ball as he stretched for the goal line, resulting in a touchback.

Cousins' fumble early in the second half led to an easy Eagles touchdown.

"Clearly I've got to coach it better," O'Connell said. "Ball security is a major major focus in our football philosophy. But clearly, I need to do a better job."

Fumbling may prove to be a temporary, if costly, problem. The Vikings' line play remains a dire threat to a promising season.