When Arsenal signed Bernd Leno from Bayer Leverkusen in June, it seemed that Unai Emery had found a new first-choice goalkeeper for the Gunners.Petr Cech, who turned 36 in May, is no longer the world-class keeper of yesteryear and a change of personnel in between the sticks appeared necessary.However, it was the veteran former Czech Republic international who got the nod for Arsenal’s first Premier League game of the season against Manchester City on Sunday afternoon.This came as a big surprise - and a disappointment - to the Arsenal supporters.Against Pep Guardiola’s league champions, they wanted to see their new summer signing in goal rather than the ageing Cech, whose best days are clearly behind him.Arsenal went on to lose the match 2-0, although little blame could be attributed to Cech, who actually enjoyed a reasonably decent game.

He pulled off a couple of excellent saves - including a one-on-one with Sergio Aguero - and proved he still has something to offer at the highest level.

Leverkusen posted two tweets after Cech's gaffe

However, there was one incident midway through the first half which very nearly turned into the most embarrassing moment of Cech’s professional career.

While attempted to pass the ball to Shkodran Mustafi, Cech watched on as the ball rolled out for a corner, missing the far post by a matter of centimetres.

It would have gone down as one of the worst - if not *the* worst - own goals of the Premier League era had it gone in.

Cech was the most relieved man inside the Emirates Stadium as the ball went out for a corner instead.

This incident then prompted Bayer Leverkusen, Leno’s former employers remember, to post two rather eyebrow-raising tweets.

The second tweet was a video of Leno playing out from the back and setting up a Leverkusen goal.

Cech has now responded with his own tweet

Both tweets went viral - but Cech has now issued a firm response to Leverkusen…

“.@Arsenal we share important values which make us a big club not only on the football side,” Cech tweeted.

“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”.

Ouch. Leverkusen’s tweets clearly hit a nerve with Cech.

In fairness, though, he had every right to issue a response - and it’s hard to disagree with his comments.

While Leverkusen would plead that they were simply sticking up for Leno, they failed to take Cech’s feelings into consideration.

And after everything that he has achieved in the game, the tweets were rather disrespectful and unnecessary.