Liverpool midfielder Alexis Mac Allister could allegedly find himself in hot water with the FA over a social media comment about his side's controversial 2-1 loss to Tottenham Hotspur.
Jurgen Klopp's men travelled to North London on the back of a seven-game winning streak, while also aiming to protect a 19-match unbeaten run across all competitions.
However, the Reds lost for the first time in nearly six months in the capital, thanks in no small part to an inexcusable officiating error, which saw a Luis Diaz goal wrongly ruled out for offside.
The Colombian's 34th-minute effort would have put the Reds 1-0 up, but the linesman's flag went up straight away, and play resumed from a Tottenham free kick after a quick VAR check.
Replays showed that Cristian Romero was playing Diaz onside, which was spotted by the VAR room, but Darren England allegedly thought that the goal had been given on the field, hence the short review.
By that point, Liverpool had already lost Curtis Jones to a red card for a crunching tackle on Yves Bissouma, before Son Heung-min broke the deadlock just two minutes after Diaz's disallowed effort.
Liverpool still managed to claw their way back into the match through Cody Gakpo, but Diogo Jota then saw red for two yellow-card challenges on Destiny Udogie, who appeared to clip his own heel for the Portuguese's first booking.
Despite having two fewer men on the field, Klopp's side defended magnificently, only to have all their hard work undone by a Joel Matip own goal in the sixth minute of second-half injury time.
As Tottenham players rejoiced on social media, Mac Allister weighed in on compatriot Romero's celebratory post, commenting: "Normal when you have 12 players" in a dig at the officials.
The Spurs defender bit back at his Argentina colleague with the response: "Cry at home", and according to The Sun, Mac Allister could now be facing an FA charge for questioning the integrity of on-field referee Simon Hooper.
The ex-Brighton & Hove Albion man has already had one dealing with the governing body this season, although it was a positive one, as his three-match ban was overturned after he was adjudged to have been wrongfully sent off against Bournemouth.
In response to the PGMOL's admission of a "significant human error" on Saturday, Liverpool released a statement claiming that such an explanation was "unacceptable" and will explore a range of options given the "clear need for escalation and resolution".
In the meantime, Klopp will prepare his troops for Thursday's Europa League group-stage fixture at home to Union SG, which precedes a trip to Brighton in the Premier League on Sunday afternoon.
As things stand, Jones and Jota will both miss the Seagulls clash through suspension, while Gakpo went off injured immediately after scoring on Saturday, and Klopp offered a pessimistic update on the Dutchman's condition after the game.
