The Swiss international was sent off for a nasty, high-boot challenge on Diogo Jota during Arsenal's Carabao Cup semi-final first leg against Jurgen Klopp's men at Anfield.
It left his side to play with a numerical disadvantage for more than 70 minutes while Mikel Arteta also switched to a back-five thereafter in a tactical move.
Yet the Gunners were able to avoid defeat, putting up a spirited defensive performance which kept the home side at bay in a 0-0 draw.
After the game, Xhaka put up a message on his official Instagram handle where he regretted the moment but applauded his side for their performance.
"I want to apologise to everyone. I am so proud of my team and the spirit that they showed to keep a clean sheet tonight."
This was Xhaka's fifth red card since joining Arsenal. No player in the squad has been sent off more often than the Swiss midfielder during this period.
He's now suspended for the decisive second leg at the Emirates next Thursday.
It compounds Arteta's midfield woes as he's already running short of options in the position.
Ainsley Maitland-Niles has joined AS Roma on loan, while Thomas Partey and Mohamed Elneny are away at the African Cup of Nations.
Now with Xhaka also unavailable for the return fixture, Arteta will have a massive selection headache as Arsenal look to reach the cup final.
Arsenal are in Premier League action against Tottenham Hotspur in the North London derby on Sunday.
Xhaka's poor disciplinary record highlighted by his red card
Xhaka has now been sent off five times in Arsenal colors since joining the side in 2016.
No Premier League player has seen more red cards than him in all competitions during this period.
His latest debacle - a silly-but-dangerous challenge on Jota - once again highlighted the Swiss international's propensity to lose focus.
This has often landed the Gunners in hot water, such as in the 5-0 defeat to Manchester City earlier this season and the 0-1 loss to Burnley in the 2020-21 season.
Although his side avoided humiliation last night, thanks to a resolute display in defense, they won't have such luck every time.