Arsenal fans have fumed at Atletico Madrid for what they believe was a “dark art” during their Champions League semi-final first-leg.
The English side travelled to Spain on Thursday morning (AEST) in search of a first Champions League final in 20 years.
Both teams scored penalties in a 1-1 draw ahead of next week’s second leg in London.
But it was a moment at halftime which rattled Arsenal supporters.
Journalist John Cross shared an image on social media that appeared to show just the left side of the pitch being watered by the sprinklers — the half Arsenal would be defending.
He also added the caption: “A cynic might say Atletico are only watering the end of the pitch Arsenal will be defending in the second half…”
The inference was Atletico were doing this in an attempt to make the pitch slick for their attacks, while Arsenal would have to deal with a dryer surface when they go forward.
Cross did add a caveat one minute later which read: “In fairness, bit more of an even spread now.”
However, that did not stop Arsenal fans from reacting furiously on social media as they bemoaned the implied tactic being carried out at the Metropolitano Stadium.
Mi Dazolam said: “How is that allowed?”
Gondo Andy added: “Some dark art of the game.”
ArsenalBod replied: “Let’s see the uproar if we do the same at the Emirates.”
While E Quello Che E said: “(Not hating on the tweet) but for this to be a talking point in the modern game is insane. But I don’t think this should be allowed, Either water the whole pitch or nothing at all.”
Arsenal were leading 1-0 at halftime thanks to Viktor Gyokeres’ penalty, before Julian Alvarez levelled from the spot after the break.
Prior to the game, Arsenal called for a pitch inspection as they felt the length of the grass was too high — a complaint that was dismissed by Uefa.
Guillem Balague told CBS Sports: “I need to tell you about the grass war that took place just about an hour ago because Arsenal’s ground staff came in thinking the grass is too high. They were not happy with it.
“They asked Uefa to actually measure it. They weren’t happy, they thought that it was Simeone creating some dark arts.
“After a while Uefa said no, it’s actually 26mm. The limit is 30mm and it goes between 21mm and 30mm.
“It’s 26mm which, by the way, was the same when they played Barcelona here.”
The pitch at the Metropolitano Stadium has been criticised for much of the season, with players slipping more frequently than normal.
Arsenal and Atletico Madrid head to the Emirates on Tuesday knowing they are both two games away from their club’s first ever Champions League trophy.
Arsenal’s only Champions League final came back in 2006 when they lost 2-1 to Barcelona.
Atletico were beaten 4-0 by Bayern Munich in a replay in 1974, before they lost to city rivals Real Madrid in the 2014 and 2016 finals.