Petr Cech became embroiled in a social media spat with Bayer Leverkusen after the Bundesliga club's Twitter account mocked an error made by the Arsenal goalkeeper against Manchester City.
Cech was selected to face City on Sunday ahead of new Arsenal signing Bernd Leno, who joined the Gunners from Leverkusen in the close season.
But the former Chelsea star almost scored one of the most embarrassing own goals of all-time in Arsenal's 2-0 defeat against the Premier League champions.
Cech attempted a pass across the face of his own goal that almost crept into his unguarded goal to the horror of new Arsenal boss Unai Emery.
Leverkusen's English account picked up on Cech's narrow escape, replying to one tweet highlighting the error.
"We might know a guy..." they tweeted, seemingly suggesting their former number one Leno would be more adept at implementing Emery's vision of passing out from the defence.
That was followed by a video of Leno playing out from the back in a game for the German side, with the caption: "In case you were all wondering how to play out from the back..."
Retweeted over 2,200 times, plenty of supporters of both clubs found the reply humorous, but Cech took to Twitter to post a reply on Monday evening, criticising the post.
"@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 ," Cech wrote.
Leverkusen's account replied to Cech's tweet soon after - saying their original "joke" had been taken more personally than it should have been.
It read: "Hi Petr. It seems our joke about wanting to see Leno, our former player, in action has been taken a bit more harshly/personally than intended. It was only a bit of banter. We're all for the values you've stated and wish you and your big club all the best. Nice 1v1 save on Aguero!"
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