When Jofra Archer struck Steve Smith with a searing bouncer that left the champion batsman dazed and most spectators deeply concerned, it did not seem England's new weapon had done much to advance the cause of Australian cricket.
Yet once it was clear the next day Smith was concussed but, given the worst-case scenario, in relatively good health, there was one consolation for the game here.
Archer's menacing spell encapsulated by the single delivery that struck Smith's unprotected neck came as Cricket Australia was pushing the case for the mandatory use of helmets at all levels.
More than one million Australian viewers held their breath after Smith suffered that sickening blow. They were given a jolting reminder of the damage that can be done by 163 grams of cork, tightly-wound string and hard-stitched leather hurled from 22 yards.
Of course, tragically, the Australian cricket community had an even more chilling demonstration of the game's often unspoken danger when Phillip Hughes' died from injuries suffered when he was struck by a bouncer in a Sheffield Shield game at the SCG in November 2014.
After Hughes's death, Cricket Australia commissioned the Curtain Review which recommended improved safety standards. This, in turn, led to some changes in equipment and the concussion protocols practised at Lord's.
Around the same time helmets for juniors became mandatory. Now, after a period to allow equipment manufacturers to achieve the universally adopted British Standard, Cricket Australia is this season recommending that all local associations make helmets compulsory for batsmen, wicketkeepers when up to the stumps and close-in fielders.
Inevitably, however, this move to mandate the use of helmets in club competitions and particularly veterans competitions (typically for players aged over 40) has been met with some stubborn resistance.
"There's no one as fast as Jofra Archer bowling in the fifths," will be the typical response of the local legend defending his right to take guard in a club cap or Greg Chappell floppy.
Never mind that, anecdotally, the majority of head injuries to batsman not wearing helmets occur when the ball flies from the now much meatier edges of bats into the head.
But if this attitude seems self-destructive some of us don't have to look far beyond our own nets to understand why it is taking Cricket Australia some time to gain universal support for a common-sense policy.
A small confession — I have played club cricket on and off for 40 years and, even in recent seasons when my reflexes were even slower than my running between the wickets, I have never worn a helmet.
As a junior, the only cricket helmets were clumsy prototypes including the modified motorcycle helmets worn by Englishmen Dennis Amiss and Tony Greig during World Series Cricket.
Amiss once said his helmet had a visor that "could withstand a shotgun blast at 10 yards". This was the minimum required to keep out the bullets bowled by Michael Holding, Andy Roberts and others.
But while Amiss and Greig chose survival over fashion there remained a strong cultural resistance to helmets.
As a child of the 70s who grew up watching Viv Richards hook Dennis Lillee and Jeff Thompson off his eyebrows wearing nothing more than a thin cloth cap, the very idea of helmets was somehow anathema.
The bumps and bruises suffered by batsmen struck by bouncers were worn as medals of honours. Rick McCosker batting with a broken jaw in the Centenary Test is just the most celebrated instance of a player whose bravery was lauded even when it defied common sense.
Entering senior cricket as a 15-year-old the ethos was to win 'em and wear 'em. Even now a sharp blow to the rib cage brings a chorus of "don't rub it" from the slips. To flinch in the face of fast bowling, or even the suburban trundler, is still considered a manifest sign of weakness.
More recently lack of comfort and familiarity is cited by those club players who did not become acquainted with the now-much-improved protective headwear as juniors.
When you've worn a lightweight cap all your cricketing life helmets can feel heavy, cumbersome and even change your balance at the crease and obscure your vision. The failure of Test players including Smith to wear stem guards that protect the neck shows comfort has trumped safety even for those facing Archer's extreme heat.
Yet even allowing for the much slower bowling in lower grade club cricket the argument for compulsory helmets is compelling.
Even at the best organised local clubs, SCAT (Sports Concussion Assessment Tool) is what you yell at a dog that has run onto the field and there is not the kind of medical support being used to minimise the risk of serious injury or even death in first-class cricket.
So this season I am buying a helmet and plan to wear one in a game for the first time. Not just for my personal safety but to set an example to the younger players who might feel tempted to discard their lids.
Yes to my generation a helmet can feel heavy and uncomfortable and this discombobulation might chisel a run or two off an already slender batting average. But it might also add several years to a lifespan.