Lautaro Martinez had the ball in the net twice during the derby with Milan, but Semi-Automatic Offside Technology disallowed the Inter striker’s second for the tightest of margins.
The game ended 1-0 with a header from Lautaro Martinez on the Hakan Calhanoglu corner.
Nerazzurri supporters had also cheered another goal from the Argentina international, before it was flagged offside.
It was evident even at the time that it was a very tight call, but not until the Semi-Automatic Offside Technology replay did it become apparent quite how close.
Lautaro Martinez was offside with a sliver of his forehead and part of one shoulder.
If the area of the body can be used to legally score a goal, then that qualifies for an offside call, no matter how small.
The SAOT was introduced in Serie A for the second half of the season and uses multiple cameras keeping track of dozens of points on the bodies of every player to make sure the result can come through quickly and accurately.