Manchester United defender Lisandro Martinez got away with what looked a clear foul on Mo Salah against Liverpool.
Midway through the first half, the Egyptian King was marauding along the right flank and seemed set to initiate a goalscoring opportunity for the Reds.
However, his progress was halted when the Argentine defender came across to block him, appearing to have used his arm at head-height on the 30-year-old forward.
Despite the incident happening very close to the assistant referee on that flank, he didn’t wave his flag for a foul, nor did Andy Madley penalise Martinez for what looked a clear breach of the rules.
How the officials failed to blow for that obvious obstruction is incomprehensible.
You can see a clip of the incident below from Sky Sports’ coverage of the game, courtesy of @Jaspairee on Twitter: