A tale of three penalties at the Metropolitano six days ago. Viktor Gyökeres converted from the spot just before half-time after being fouled, giving Arsenal the lead. Julián Álvarez equalised ten minutes into the second half following Ben White's handball. Arsenal were left furious when a late penalty was overturned after a VAR review, with replays showing Eze appearing to be fouled by Hancko inside the box — a decision that provoked visible rage from Arteta on the touchline. The 1-1 result leaves Arsenal with a marginal but real advantage heading into the Emirates. The Gunners have progressed from eight of their previous ten European ties when avoiding defeat away from home in the first leg — including each of the last five. Arsenal have lost only two of their last 23 Champions League matches (W17 D4), both against PSG in last season's semi-finals.

Arsenal arrived into Tuesday in superb domestic form — Gyökeres bagged a brace in a routine 3-0 win over Fulham, moving six points clear of Manchester City at the top of the Premier League. Saka ran the show before being withdrawn as a precaution — his full return to fitness is Arsenal's single biggest boost heading into the second leg. Arsenal average 2.6 goals per game in the Champions League this season when Saka plays, compared to just 1.5 without him. Arteta has confirmed Ødegaard (knee) and Havertz (muscle) will both be available. Timber (groin) and Merino (foot) remain out. Predicted lineup (4-2-3-1): Raya; Mosquera, Saliba, Gabriel, Hincapié; Zubimendi, Rice; Saka, Ødegaard, Eze; Gyökeres.

Simeone rotated heavily for the La Liga weekend and has since named his 25-man travelling squad. Álvarez — who was forced off with a suspected ankle injury after scoring — has been included and should be fit to start. Giuliano Simeone and Sørloth have overcome knocks to travel. Giménez could play a part after recovering from muscle injury. Only Barrios and Nico González (both thigh) are absent. Atlético progressed from six of their previous ten European two-legged ties when drawing the first leg at home. Their away record is the concern — just one win in their last seven away games in the Champions League knockout stages, though that win came at the Camp Nou against Barcelona. They have been beaten in six of their last seven UCL encounters against Premier League opposition. Predicted lineup (4-4-2): Oblak; Pubill, Savić, Witsel, Hancko; G. Simeone, Cardoso, Koke, Lino; Griezmann, Álvarez.

Arsenal set a new club record for their longest unbeaten run in the Champions League (14 matches) if they progress — ending their 20-year exile from the final. The Emirates Stadium is hosting a semi-final second leg for the first time since the ground opened. Arsenal's defensive record under Arteta in the Champions League is the best of any manager with 20 or more games in the competition — averaging just 0.65 goals conceded per game across 37 games. Atlético's set-piece vulnerabilities are the other side of that coin: nine goals conceded from corners and wide free-kicks this season. With Rice and Saliba dominant in the air, Arsenal's dead-ball threat could be the decisive weapon.

Arteta said: "We are in an incredible position. We have to play in front of our people. It's in our hands." Gyökeres added: "We know when we play at home with our fans, it's going to be different. We just have to do our job." Simeone, reflecting on the first leg: "Rarely have we seen such enthusiasm from the fans as we had at the start. They won't all be there for the second leg, but their hearts and souls will be." Álvarez, linked with a move to Arsenal itself, brushed the rumours off: "I try not to pay too much attention. I want to focus on what we're doing — it's the most important time of the season." Scoring the goal that eliminates the club reportedly pursuing him would be one of football's most delicious ironies. Griezmann's farewell European campaign also adds emotional texture — his Champions League story with Simeone, spanning two finals lost to Real Madrid, deserves a different ending.