Petr Cech turned his rage on Bayer Leverkusen's Twitter account after the Geman club jokingly suggested Bernd Leno might fare better in the Arsenal net.
Despite the arrival of the German goalkeeper, Cech retained his first-team spot for Sunday's Premier League opener against Manchester City.
And while Arsenal finished on the end of a 2-0 defeat, the veteran shot-stopper prevented City running away with the game at the Emirates Stadium with a handful of key saves.
A nervous moment playing the ball out from the back, however, caught the eye of Leno's former employers.
At one point Cech received possession with City in hot pursuit, and sliced the ball behind his own goal in panicked fashion.
"We might know a guy..." Leverkusen's English Twitter account replied to a video of the gaffe, and proceeded to share a goal scored by the Bundesliga club that was started by Leno in his own area.
As internet trolling goes it was a fairly playful tease, but Cech failed to find the funny side as he let loose with his own Twitter response.
"At Arsenal we share important values which make us a big club not only on the football side," the keeper explained, in a post that mentioned Leverkusen at the end.
"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."
Leverkusen have since replied, claiming that their tweet was "just a bit of banter" while apologising to the goalkeeper for any offence that may have been caused.
Is Cech justified in his anger, or is he making a mountain out of a molehill? Let us know what you think about this bizarre social media spat below.
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