With the Gunners trailing 1-0 with just under 10 minutes to go at the Emirates Stadium, Arsene Wenger raised eyebrows by turning to the veteran defensive midfielder - and those eyebrows nearly catapulted off their owners' faces when the Frenchman brought down Lionel Messi in the box with his very first action of the game.
By the time that the Barca superstar had netted the resulting penalty, Twitter was already losing its collective mind over what Flamini's blunder said about him, Wenger and Arsenal as a whole...
Mathieu Flamini: Impact Sub— Wile E Kouyaté (@tomvictor) February 23, 2016
Arsenal fans looking at Flamini like.. pic.twitter.com/tJzOYE0SBE— Football Tweets (@FutballTweets) February 23, 2016
Barcelona must be delighted they brought on Flamini.— gunnerblog (@gunnerblog) February 23, 2016
Clever by Arsene if you think about it. Bring Flamini on. Kill the tie. Focus on the league. Hard to argue with it.— YankeeGunner (@YankeeGunner) February 23, 2016
Home tie, need to score....brings on Flamini...you reap what you sow...— Dave Fitzpatrick (@evadztif) February 23, 2016
That was the most Flamini thing I've ever seen.— The Gooner Zone (@TheGoonerZone) February 23, 2016
I want to fly to London right now, hunt down Flamini and slap him in the face! This better be his last game as an Arsenal player.— Champ (@ChampChong) February 23, 2016
Not being funny if I was Flamini coming on to a standing ovation by 4 people I would have done the same.#PlasticFans— WEST HAM LONDON (@WestHamLondon) February 23, 2016
PUT A RESTRAINING ORDER ON FLAMINI IMMEDIATELY. HE CANNOT PLAY FOR MY CLUB. @Arsenal— Lacazette (@talkmarcus) February 23, 2016
When I die, replace the Emirates clock with an hourglass containing my ashes, so Flamini can waste my time long after I've gone— Mark White (@MARK_WH1TE) February 23, 2016
If my son ever asks why I went to jail,— Ozilicious (@Goonerboy_49) February 23, 2016
"KID, IT ALL STARTED WHEN FLAMINI GAVE AWAY THE PENALTY AGAINST BARCA "
Flamini is the billionaire co-owner of a biotech company that turns waste into energy. He's a footballer that turns energy into waste. #COYG— B⭐️G (@BackOfficeGavin) February 23, 2016
Arteta & Flamini contracts end on June 30. Only 127 days ...— Sam (@samuelJayC) February 23, 2016