Arsenal called for UEFA to measure length of grass at the Wanda Metropolitano before their clash with Atletico Madrid. The two clubs meet in the Champions League semi-finals on Wednesday night – with Atleti hosting the first leg – live on talkSPORT. The Gunners were not convinced the grass height was legalAFPAnd before a ball had even been kicked, the Gunners were complaining to officials. The visiting backroom staff could be seen gesticulating and arguing with men in suits on the pitch around an hour before kick-off. It is understood Arsenal claimed the grass was too long – and asked for it to be measured.Height of grass in UEFA competitions must range between 21 and 30mm – and UEFA told Arsenal that it is 26mm.View Tweet: https://twitter.com/GuillemBalague?ref_src=twsrc%5EtfwBarcelona raised a similar complaint before their quarter-final second leg in April. Meanwhile, Tottenham endured a torrid time on the Wanda Metropolitano pitch in the round of 16, with two slips leading to goals inside the opening 22 minutes. And the playing surface looks set to become a talking point once again in the semi-finals. After watching Arsenal’s Piero Hincapie and Atletico Madrid’s Koke take a tumble inside the opening minutes, talkSPORT’s chief football anchor Adrian Durham admitted: “The pitch really isn’t good.”There were unsavoury scenes outside the ground before kick-off as police clashed with home fans. Videos on social media show Spanish authorities tackling groups of Atletico fans with tear gas and rubber bullets. A small number of fans needed to be dealt with by policeGettyArsenal supporters were advised to make their way to the ground as quickly as possible.More to follow.