The evidence for how weak Georgia Tech’s blocking was in last week’s loss to Notre Dame can be found in the statistics column for longest plays from scrimmage.

After bombarding its first two outmanned opponents for 13 plays of at least 25 yards, the Yellow Jackets produced just two — a 28-yard pass and a 44-yard run — in last week’s 30-22 defeat in South Bend, Ind.

When players aren’t blocking in the second (linebackers) and third (defensive backs) levels, it’s hard for any offense, particularly a run-oriented offense like Tech’s, to produce the impact plays that can swing a game.

And Tech’s efforts were “atrocious,” according to coach Paul Johnson. He said the offense missed at least 70 assignments, more than he has seen since he was an offensive coordinator at Georgia Southern 30 years ago and triple the usual total. He said the line and the coaching staff, including himself, were to blame.

“Just got to get better at it,” Johnson said. “We’ve got to coach better at it. I’ve got to do a better job. You can have the best plan in the world. If you can’t do it, it’s a bad plan.”

There were a several reasons the Irish were able to slow Tech’s offense.

First, Tech was sometimes confused by Notre Dame’s mixed and matched defensive looks, sometimes shifting from a 4-3 to a 3-4 to a 4-4 on the same series. The Jackets worked against numerous looks during the week, but things can change when the game goes live.

To improve that, offensive line coach Mike Sewak said there has to be better communication to assure everyone knows his assignment.

For example, on a second-and-7 play in the first quarter, Tech ran an option to the left. Instead of their standard formation — a B-back behind the quarterback, the A-backs lined up off each tackle and wide receivers aligned on either side of the formation — the Jackets placed two wide receivers to the right, one to the left and one just one A-back on the right.

As Justin Thomas rolled left to make the pitch to A-back Qua Searcy, who had been sent in motion across the formation, the guard and tackle double-teamed a defensive end. Neither disengaged to move upfield to take on a linebacker or safety. Those decisions left both defenders unblocked. The linebacker forced the pitch and the safety was free to sprint upfield and hem in Searcy, who still managed to get four yards.

“We did have some mishaps trying to get to the linebacker but we are putting it on ourselves as an O-line and as a team to make sure we take care of that this week,” tackle Errin Joe said.

Sometimes the errors were simply poor fundamentals.

After a holding penalty wiped out a 23-yard Thomas touchdown run, Joe, who drew the flag, appeared to miss a block on the next play and Thomas was stopped for a 1-yard gain on second-and-17 at Notre Dame’s 33-yard line. Tech failed to convert the third- and fourth-and-long plays and missed a chance to cut into the Irish’s 16-7 lead.

“We are a grind-it-out football team. We have to run the football,” Sewak said. “We must shoulder the responsibility. We cannot have hiccups. That’s just something we haven’t done.”

Duke, Saturday’s opponent, won’t be the easiest opponent to solve blocking problems.

The Blue Devils defeated Tech 31-25 in Atlanta last season, limiting the Jackets to 282 rushing yards — they averaged 342 ground yards in 2014 — and did not record a running play of 25 yards or more. The core of that Duke defense returns in defensive linemen A.J. Wolf and Carlos Wray, and linebacker Jeremy Cash.

The Jackets expect Duke’s defense will tweak that same game plan with some wrinkles gleaned from what Notre Dame did.

“They will probably have a better idea how to play us than Notre Dame did,” tackle Bryan Chamberlain said. “It’ll probably be just as big as a challenge.”