SOUTH BEND — I wanted to blame Notre Dame’s 35-21 loss to Oklahoma on Tommy Rees. It’s only natural. Rees has been a whipping boy for the Irish for four seasons.

But I’m not going there this time.

I’m not even going to bother parceling out portions of responsibility to the quarterbacks, the offensive line and the receivers. All of it is part of the problem but the larger, more distressing issue lies with the defense.

Expectations were tempered in all sorts of ways for this team after Everett Golson was kicked out of school for a semester, but a persistent preseason theme revolved around a solid defense with Louis Nix and Stephon Tuitt anchoring a very good line and a secondary that was “splendid”, according to the Los Angeles Times. There were lots of people and publications that echoed this theme.

They haven’t met those expectations.

On Saturday, they were bulldozed by junior quarterback Blake Bell with a monstrous second half, just like they were destroyed by Devin Gardner when they lost to Michigan.

The best chance the Irish had to win the game against Oklahoma evaporated when Bell returned from the locker room in the fourth quarter after going down with cramps. It was warm at Notre Dame Stadium and it wasn’t because the team was lighting up the field.

Notre Dame coach Brian Kelly will talk ad nauseum about how his team has to play near flawless football to beat an Oklahoma caliber football team but the truth is, the offense was pretty good after the shaky start. Certainly good enough to keep them in the game. I’m certainly not going to take Kelly’s words about how Notre Dame did a “good job defensively against a very good offense” at face value. I never felt that way in the second half when it mattered most.

OU rushed for 220 yards and Rees was Rees, making a huge play when he hit Troy Niklas with a 30-yard touchdown pass with 14:10 left that brought Notre Dame to within six points of the lead, while occasionally throwing into double coverage or failing to get the ball off time.

That’s to be expected.

Less than two minutes later, after the Nicklas TD, Bell found Sterling Shepard for a 54-yard TD pass.

All the good work the offense had done was wiped out with one explosive play.

Appropriately enough, the Sooners were able to grind out the last 5:39 mostly on the ground, running on nine of the last 10 plays. Kelly talked about the spirited play of his team and the fact that the defense was “salty” at times in the second half.

But it never looked or felt Notre Dame was able to stop OU.

They rushed for 212 yards and they passed for 238. Bell was never close to getting sacked and I didn’t see the ball quiver precariously in the hands of a Sooner ball carrier once.

They did play their familiar style of bend-but-don’t-break defense, but it was pretty clear that Oklahoma was stronger than them up front and they made them pay.

If there is a possible solution to some of the defensive problems, it could be the dual play of Rees and Andrew Hendrix, which was effective in the first half.

The last time there was a concerted, serious effort to use a two quarterback system — when the Irish played Florida State in the Champions Bowl in 2011 — the offense ran like a Chinese fire drill.

Neither Rees nor Andrew Hendrix could find the endzone then with a telescope and bazooka.

Notre Dame unveiled a respectable compromise to what has ailed the team all season.

Rees played the role of drop back, hand it-off-safely pro style QB.

And Hendrix entered in running situations.

The duo has at least added some energy to what seemed like an unsolvable problem: How to turn Rees into more than just a game manager.

The Irish can get away with that style against Purdue and Michigan State, even apparently why tipping plays.

But the good teams, like OU and Michigan and USC, require a productive, efficient offense. That means they have to score.

There was one well-played scoring drive, with Rees completing all three passes for 36 yards, Hendrix making a cameo and running for two yards and the Irish rushing for 55 yards on the drive, which ended with a touchdown catch by TJ Jones.

The two quarterback system is something for the Irish to build on. As Kelly pointed out, they need to diversify on offense and Hendrix’s ability to run the ball gives them flexibility in that area.

It’s clear that the preseason comfort of a dominating defense was a myth and that the Irish are going to have to find different ways to finish off teams this year.