Most European leagues separate level teams by goal difference, and Serie A does not. Italy consults the results between the tied clubs first, which quietly changes what a big win is worth.
The ladder runs in an unusual order
When two clubs finish level on points, the first comparison is the two matches they played against each other, taken as a miniature table of their own.
Only if that mini-table is level as well does the calculation move on to overall goal difference and then goals scored across the season.
The order sounds like a technicality and behaves like a rule change. It rewards a different kind of season from the one goal difference rewards.
Why a thrashing counts for less
In a goal-difference league, an emphatic win over a bottom club sits in the same column as a narrow win over a title rival. Both add points and one adds more margin.
Under head-to-head, that margin only helps if the tie-break reaches the goal-difference stage, which it often does not among clubs competing for the same places.
The practical consequence is that beating your direct rivals matters more than beating anyone else convincingly. Two matches a season carry disproportionate weight.
How it shapes late-season behaviour
Clubs know their head-to-head standing against every side near them, and coaches manage the closing weeks with those specific fixtures in mind.
A team trailing a rival on head-to-head cannot close the gap by running up scores elsewhere. It has to gain a point somewhere the rival drops one.
That removes a familiar late-season storyline. Goal-difference chases, common in other leagues, largely do not exist in the Italian run-in.
Three-way ties get complicated
When three or more clubs finish level, the mini-table is built from every match played among that group, which can produce orderings that look arbitrary from outside.
A club with the best overall record can finish below one it beat home and away, simply because of how the third team's results fell.
The rule is consistent rather than intuitive. It is also settled in advance, which matters more than elegance when a European place depends on it.
What it means for reading the table
An Italian table cannot be read the way an English or Spanish one can, because the goal-difference column is not the effective separator.
Two clubs level on points may be far apart in reality, and the relevant evidence sits in two fixtures that may have been played months earlier.
Anyone previewing a run-in has to check those meetings first. The information is not visible in the standings themselves, which is exactly why it gets missed.