The first leg of Arsenal’s Champions League semifinal sees them travel to the Riyadh Air Metropolitano on Wednesday night to face off with Atlético Madrid. There have been just three past meetings between these European giants, Atléti triumphing across two legs of the 2017–18 Europa League semifinal, but Arsenal racking up four unanswered goals in the league phase meeting back in October. As both sides chase their first ever Champions League title, the stakes could hardly be higher for their upcoming duels. Arsenal must ignore the Premier League title race for one moment and focus their attention on securing a hard-fought result in Spain’s capital. Atléti, who have lost seven of their last nine amid mass rotation in La Liga , need a positive result ahead of the return fixture in north London. The knockout phase of the Champions League has already produced unbelievable moments of drama and Wednesday’s first leg between Atléti and Arsenal appears certain to deliver another instalment of chaos.…