Arsenal goalkeeper Petr Cech accused Bayer Leverkusen of lacking "professionalism and sportsmanship" after he was the subject of some social media jibes from the Bundesliga club.
Cech started for Arsenal in the 2-0 home defeat against Manchester City in their first Premier League game under new head coach Unai Emery on Sunday.
The result could have been even worse when, after receiving a back-pass from debutant Matteo Guendouzi, Cech passed the ball straight out of play for a corner, narrowly missing his own right-hand post.
Leverkusen's English Twitter account responded by posting a video of Bernd Leno – who joined Arsenal from the Bundesliga club in pre-season – beginning a passing move that ultimately led to a goal, with the caption reading: "In case you were wondering how to play out of the back".
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 failed to see the funny side, however, taking aim at Leverkusen in a post on Monday while also praising his current club.
Taking to his official Twitter account, the former Chelsea keeper wrote: "At 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."
.@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
After Cech's response, Leverkusen issued a swift apology in a reply to the goalkeeper's message.
"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," Leverkusen posted on Twitter.
"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!"
|Sarri questions Chelsea motivation after Arsenal surrender|
|Emery urges Arsenal to find balance after downing Chelsea|
|Koscielny hails Arsenal fighting spirit in Chelsea win|
|Pellegrini: It was not a good idea for Arnautovic to play|
|Iran v Oman: We´re not satisfied yet, says Al Mahaijri|
|Carbery sends Munster through and ends Exeter´s lingering Champions Cup hopes|
|Dyche defiant despite offside call|
|Hasenhuttl rates Everton win as Southampton´s best|
|Benitez looking up the table after Schar inspires win over Cardiff|
|RB Leipzig 0 Borussia Dortmund 1: Witsel restores six-point cushion|
|Swansea City 1 Sheffield United 0: McBurnie punishes wasteful Blades|
|Cardiff sign Sala from Nantes for club-record fee|
|Arsenal 2 Chelsea 0: Lacazette and Koscielny fire Gunners to rousing derby win|
|Huesca 0 Atletico Madrid 3: Dominant Atleti keep pressure on Barca|
|Rashford arguably league´s best striker with Kane out - Solskjaer|
|Hafeez plays steady hand as Pakistan punish Proteas´ patient approach|
|Klopp: Exceptional Salah would have scored even more up front!|
|Suspected ´serious´ Verratti injury leaves Tuchel with mixed emotions|
|We needed to rediscover our best form - Ramos pleased for Real Madrid fans|
|City bought Guardiola four full-backs! - Mourinho aims dig at Man Utd transfer policy|
|Valverde ´not frustrated´ amid De Jong & Vela links|
|Championship Review: Leaders Leeds beaten at Stoke as Villa end Hull run|
|Bournemouth rode their luck, admits Howe|
|Barca boss Valverde calls for clarity on RFEF rules|
|Bears rack up 107 points in routing Enisei en route to quarter-finals|
|Paris Saint-Germain 9 Guingamp 0: Verratti injured for rampant champions|
|Solskjaer: I´ll remember managing United for the rest of my life|
|Palace win a ´massive relief´ for Liverpool boss Klopp|
|Salah fourth fastest to 50 goals in Premier League history|
|Real Madrid 2 Sevilla 0: Solari´s side take over third spot|
|Watford 0 Burnley 0: Wood denied winner by contentious call|
|Liverpool 4 Crystal Palace 3: Salah reaches 50 thanks to Speroni shocker|
|Newcastle United 3 Cardiff City 0: Schar double moves hosts out of bottom three|
|Southampton 2 Everton 1: In-form Saints steer clear of trouble|
|Bournemouth 2 West Ham 0: Wilson and King sink Pellegrini´s men|
|Manchester United 2 Brighton and Hove Albion 1: Record-breaking win for Solskjaer|
|Pelicans star Anthony Davis out for one to two weeks with sprained finger|
|Verratti hobbles off for PSG against Guingamp|
|Brook ponders next move after missing out on Khan|
|Mick Schumacher: The Ferrari academy graduates who made it to F1|
|Thailand v China: Lippi aims to overcome War Elephants and reach last eight|
|I deserved red card, says Wolves boss Nuno|
|Mick Schumacher joins Ferrari Driver Academy|
|Jared Goff not worried about Superdome noise: ´When it´s loud, we love it´|
|Rooney urged Rashford to run at defenders|
|Former Springbok Lambie retires from rugby aged 28|
|Spygate: EFL confirms 11 clubs have made contact about Leeds|
|When it´s loud, we love it - Goff ready for New Orleans noise|
|Wolves 4 Leicester City 3: Jota hat-trick drama piles pressure on Puel|
|´Asparagus´ Zverev joins frustrated Djokovic in round four|
|Lowry takes Abu Dhabi title at the last after ding-dong Sterne battle|
|Rooney: United should go "all out" for Pochettino|
|Djokovic frustrated by ´unnecessary´ Australian Open floodlights|
|Jordan v Vietnam: Park expecting ´aggressive´ encounter|
|Serena and Halep book blockbuster, Osaka won´t throw in the towel|
|Brady: Mahomes has had ´spectacular season´|
|Halep not intimidated by Serena anymore|
|Farrell´s Six Nations preparations hit by thumb injury|
|Pogba confident Manchester United can reach top four|
|Alexander-Arnold embodies Liverpool spirit - Klopp|
|Stoinis shoots Stars to Melbourne derby victory|
|A-League Review: Glory held in stalemate as Sydney close the gap|
|DeMarcus Cousins ´felt like a kid on Christmas´ in Warriors debut|
|Alexander-Arnold signs long-term contract at Liverpool|
|Pochettino eyes Messi-esque role for Alli|
|Halep sets up mouth-watering Serena showdown by conquering Venus|
|Wilder-Fury II expected for April 27 or May - Warren|
|Celtics´ Kyrie Irving on technical: If someone questions your manhood, you got no choice|
|Serena would ´love´ Halep clash|
|Djokovic sees off Shapovalov at Aus Open|