Arsenal's ground staff demanded UEFA conduct an emergency pitch inspection at the Riyadh Air Metropolitano just an hour before tonight's Champions League semi-final first leg against Atletico Madrid.
The Gunners' backroom team arrived at the stadium convinced the grass had been deliberately grown too long, immediately suspecting gamesmanship from the Spanish hosts.
Journalist Guillem Balague, reporting from the scene for CBS Sports, said: "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 thought that it was Simeone creating some dark arts."
Arsenal were not happy with the length of grass at Atletico Madrid's ground
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UEFA officials swiftly responded to the complaint, conducting measurements of the playing surface on site.
The inspection revealed the grass stood at 26 millimetres, comfortably within the governing body's permitted range of 21 to 30 millimetres.
Balague confirmed the outcome: "After a while, UEFA said, no, it's actually 26 millimetres. The limit is 30, because between 21 and 30 is 26."
The measurement matched the exact grass length recorded when Barcelona visited the same venue earlier in the competition.
With Atletico found to be fully compliant with regulations, Mikel Arteta's side have no choice but to accept the conditions and focus on the match itself.
Arsenal are not the first visiting side to raise concerns about the Metropolitano pitch during this season's Champions League knockout rounds.
Arsenal's complaints fell on deaf ears as UEFA officials denied them their request
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Barcelona lodged a similar complaint when they faced Atletico in the quarter-finals, with manager Hansi Flick publicly criticising the grass length, claiming it was designed to slow down his team's passing game.
Tottenham also expressed frustration during their earlier tie against Simeone's side, with Spurs players alleging the surface had been excessively watered.
The pattern of complaints from high-profile opponents suggests visiting clubs remain deeply suspicious of conditions at the Spanish club's home ground.
Antonin Kinsky made two shocking errors after 15 minutes against Atletico Madrid as Spurs went 3-0 down | GETTYThe playing surface proved particularly problematic for Tottenham during their visit to the Metropolitano.
Goalkeeper Antonin Kinsky endured a nightmare first half, committing two costly errors that forced his manager to substitute him before the interval.
Defender Micky van de Ven also lost his footing on the turf as Atletico capitalised on their opponents' difficulties to progress in the competition.
Arsenal, who defeated Sporting in the quarter-finals thanks to a late Kai Havertz goal, are bidding to reach their first Champions League final in two decades.
The north London club last contested European football's showpiece event in 2006.