Every week we sit like unmerciful accountants and count mistakes, note flaws and classify slip-ups. We are experts in athletic errors. This past weekend, for example, the defending French Open champion Jelena Ostapenko collected 48 unforced errors, Rory McIlroy hit three spectators and the Celtics went 7-of-39 from three-point range in Game 7 against the Cavs.

But the error, as Liverpool goalkeeper Loris Karius knows, has a ranking system. Some errors are routine and shrugged off and others scar the brain like an unremovable lesion. If Ostapenko was faulty, and McIlroy was guilty of a stumble, then his was a cruel howler. The stuff from narcotic nightmares.