By Ed McGranahan.

By Ed McGranahan

A deep sigh would be appropriate about now.

Don’t underestimate what beating Boston College, 45-31, meant for Clemson today and tomorrow.

Coming out of Tallahassee and heading into Chestnut Hill, concern with the defense reached orange alert, which is defined as a high risk of attack.

Boston College delivered a sneak attack.

In the first half alone, BC took the wraps off 10 formations it hadn’t shown the first three games. BC battled back from a 10-point deficit to take the lead with 4:12 to play in the first half and, after trailing by 17 in the second half, made Clemson squirm with quarterback Chase Rettig and receiver Alex Amidon slicing off huge chunks of real estate.

Yet when Dabo Swinney decided to gamble on fourth down in the fourth quarter rather than punt to protect a 14-point lead, the defense bailed him out.

And when Tajh Boyd coughed up the ball in the fourth quarter Saturday, the defense bailed him out.

“We saw them grow up right before our eyes in the second half,” Swinney said of his defense.

Indeed, he may be correct.

Rettig faced little more than token pressure much of the game. Coverage was an illusion. Clemson was capable against the run but struggled to secure a grip on Rettig and Amidon. The ACC’s most prolific quarterback the first month of the season, Rettig was as billed with Amidon – anybody else think of Welker with long hair – his primary target.

A week ago the momentum turned and Clemson never recovered. In this game, Clemson turned the table.

Shorthanded offensively with the loss of Sammy Watkins and Martavis Bryant to illness and injury, Clemson did not look as if it was playing with a spare tire.

Injured here two years ago, Andre Ellington exacted vengeance with 132 yards and a touchdown.

As he did when Watkins sat out the first two games, Nuke Hopkins delivered another record performance with a record 197 receiving yards and a touchdown. Replay officials covered Hopkins better than the BC secondary, stealing two other touchdowns.

And after challenging his teammates last week, quarterback Tajh Boyd walked the walk. We’ve come to expect performances like 28 of 38 for 367 yards and three touchdowns. His relentlessness as a runner makes him doubly threatening. That play on which he lowered his shoulder and willed himself forward for the first down was a defining moment for Boyd.

Yet even with the impressive offensive numbers — 576 yards, 27 first downs and 10 of 16 on third down — defense ultimately secured the game.

Brent Venables didn’t wave a wand. There wasn’t any magic. It was about deciding that the defense was going to take its lumps this season, and Venables had to give it room to fail. So he ran out anybody on the roster that had a shot at making a play.

Rather than wait on the line to generate more than a token pass rush, Venables sent blitzes from every corner of the universe. Safety Rashard Hall, struggling to recapture his coach’s respect in Venables’ scheme, knocked Rettig out of the game briefly with a crushing tackle off a blitz.

Corner Garry Peters, in for shell-shocked Darius Robinson, intercepted a pass after the botched fourth down at the Clemson 46.

And when Boyd fumbled at the Clemson 33, the defense forced BC to turn the ball over on downs at the 28-yard line with 4:02 to play.

The much-maligned rush defense limited BC to 51 yards. BC was 5 of 17 on third down.

Travis Blanks, DeShawn Williams and Bashaud Breeland all had moments that should play well over the final seven games.

Yes, this may have been a turning point for the defense.

We’ll know more after Georgia Tech.