Arsenal’s Petr Cech was in a mood on Monday as minutes after firing off a riposte to Bayern Leverkusen for what he perceived to be an insult, the Czech veteran casually shut down a troll on Twitter with just one line.

First, some context.

On Sunday, Arsenal were humbled in their own backyard as defending champions Manchester City beat them 2-0 in their season opener.

While Cech was among the few Arsenal players to have a decent game, he struggled to cope with City’s high pressing and new coach Unai Emery’s insistence of playing your way out of trouble, instead of hoofing it at the first sign of danger.

One Arsenal fan inadvertently kickstarted a raging debate on Twitter when he posted this unflattering GIF of Cech attempting to play the ball out:

Cech 😩😩😩 pic.twitter.com/o4WSe4gCH5

— Terje (@ArsenalTerje) August 12, 2018

With summer signing Bernd Leno waiting in the wings, speculation is rife that the German custodian will eventually take over the No.1 jersey at Arsenal.

And his former club, Bayer Leverkusen, had a cheeky response to the aforementioned tweet:

We might know a guy…

— Bayer 04 Leverkusen (@bayer04_en) August 12, 2018

Leaving no doubt that they were in fact referring to Leno, Bayer tweeted this video of a rapid counter-attack:

In case you all were wondering how to play out of the back… pic.twitter.com/LZkxznsGPs

— Bayer 04 Leverkusen (@bayer04_en) August 12, 2018

Cech took umbrage at the jokes being made at his expense and his terse statement effectively shut down all the trolls:

.@Arsenal we share important values which make us a big club not only on the football side . Fair competition, professionalism and sportsmanship are the biggest ones you teach young footballers and it’s sad to see when other clubs don’t share the same values. .@bayer04_en

— Petr Cech (@PetrCech) August 13, 2018

However, one twitter user remained defiant and actually made an astonishing claim:

Professionalism? How can you talk about professionalism when you haven’t improved your distribution after nearly two decades of training? You’ve embarrassed yourself, your club and the supporters. https://t.co/O0ucDIdm5N

— RG (@registability) August 13, 2018

The troll, who goes by the twitter handle registability, is a UEFA B-Licence coach and a psychologist, according to their profile bio.

Cech wasn’t impressed and responded with a terse one-liner:

Maybe try to google what professionalism really means … https://t.co/PduZrS251e

— Petr Cech (@PetrCech) August 13, 2018

The troll remained unfazed, however, and had another jibe to add:

Part of being a professional is dedicating yourself to improving on your weaknesses, something which you have failed to do. Take responsibility instead of playing the victim. https://t.co/YpBBVhrEtj

— RG (@registability) August 13, 2018

Cech didn’t respond to this latest escalation, but it’s safe to assume he doesn’t agree with that line of though.

DON’T MISS | Arsenal custodian Petr Cech bristles at Bayer Leverkusen’s attempt at trolling on Twitter

With an away clash at crosstown rivals Chelsea looming large, Gunners fans will hope Cech puts aside all the flak he’s receiving on social media and just focuses on training.

The Blues, also under a new coach with a different philosophy, thrashed Huddersfield Town 3-0 away on Saturday and will definitely be the more confident of the two sides when they resume rivalries on August 18.