Tech moves fast, but you're still playing catch-up?

That's exactly why 200K+ engineers working at Google, Meta, and Apple read The Code twice a week.

Here's what you get:

All delivered twice a week in just 2 short emails.

Join 200K+ engineers

This is an advertisement. Clicking on it helps me run this newsletter and website*

Viktor Gyokeres scored twice when we last faced Atletico Madrid at the Emirates in October, in a 4-0 demolition. Six months later, we go to the Metropolitano knowing that scoreline means almost nothing now as we try to reach the Champions League final for only the second time in our club's history.

Almost everything about our circumstances has changed since that night. We were at full strength in October, flying domestically, and carrying the kind of ruthless momentum that turns matches into processions. We controlled possession, dominated the press, and tore Atletico apart in a devastating 13-minute spell after half-time with goals from Gabriel Jesus, Martinelli and that Gyokeres brace. That was a different Arsenal. Tonight, we go to Madrid wounded.

Arteta confirmed on Tuesday that Kai Havertz is out after limping off against Newcastle with a muscular issue. Jurrien Timber, who has been absent for over a month with a groin injury, is not in the squad. Mikel Merino has been sidelined since February with a broken foot and will not play again this season. That is three first-choice players missing for one of the biggest game of the campaign.

Bukayo Saka returned off the bench in the Newcastle win after five games out with an Achilles problem. He looked sharp in his cameo but has not started a match since the Carabao Cup final on March 22. Asking him to go from the bench at the Emirates to starting a Champions League semi-final in Madrid four days later is a significant physical and psychological step. Eberechi Eze, who scored the winner against Newcastle, is fit after being withdrawn as a precaution. Martin Zubimendi came off with illness on Saturday but is expected to be available.

In October, Arteta could pick from a nearly full squad and build the exact game plan he wanted. Tonight, he is patching together a side with limited options on the right, no natural Havertz replacement in the half-spaces, and a defence that has been operating without its first-choice right-back for six weeks. The depth of this squad is about to be tested in the most demanding environment possible.

Here is the schedule that makes tonight's teamsheet so agonising. We play Atletico in Madrid on Wednesday and three days later we host Fulham in the Premier League. Three days after that, on Tuesday, we play the second leg at the Emirates. Then West Ham away the following weekend.

We have up to nine matches in less than four weeks, with a Premier League title and a Champions League trophy both in play simultaneously. Every selection decision Arteta makes tonight has a knock-on effect on Saturday. Saka's minutes in Madrid have to be weighed against what we will need from him on Saturday. Every ounce of energy Rice expends pressing Koke is energy he will not have three days later.

Manchester City do not have this problem. They were knocked out of the Champions League by Real Madrid in the last 16. Their remaining schedule is five Premier League games, the rearranged Crystal Palace fixture, and the FA Cup final against Chelsea on May 16. They are three points behind us with a game in hand, and Guardiola can rotate with fewer fixtures to manage. We don’t have that luxury. A slip against Fulham because of European fatigue and the title race will almost be over. A loss of focus against Atletico because of the league and the Champions League dream will die.

This is the price of being in both races, and I would not swap it for anything. But it means Arteta has to manage minutes with surgical precision tonight.

Simeone's approach in this season's knockout rounds has followed a clear pattern: take the first-leg lead at home, then absorb pressure in the return fixture. They beat Tottenham 5-2 at the Metropolitano in the last 16 before surviving a 3-2 second-leg defeat at Spurs to go through 7-5 on aggregate. They won 2-0 at Barcelona in the quarter-final first leg and then weathered a 2-1 second-leg defeat to advance 3-2 overall. The template is obvious. Simeone wants to give his team something to hold onto before the second leg arrives.

Julian Alvarez is the focal point for the team. His nine Champions League goals this season are the most by any Atletico player in a single European campaign. Opta data shows he has recorded 853 high-intensity pressures across his 13 appearances, the highest total of any player in the 2025-26 Champions League. He does not just finish chances. He drives the press, drops between the lines, and drags centre-backs out of position. If Saliba and Gabriel are not disciplined in tracking his movements, we will be in trouble.

Antoine Griezmann, playing what are likely to be his final European matches before a move to MLS, will operate in the spaces Alvarez creates. The pair have developed an understanding that makes Atletico far more fluid in attack than the low-block stereotype Simeone's teams carried for years. This is an Atletico side that has scored 34 goals in 14 Champions League matches this season, already their highest single-season tally in the competition.

The trade-off is that their defence has regressed. They have conceded 26 goals in those same 14 European games, a number that would have been unthinkable under Simeone five years ago. Pablo Barrios and Jose Gimenez are both out injured. Ademola Lookman, their January signing from Atalanta, remains a doubt after missing two matches with a muscle problem picked up in the Copa del Rey final defeat to Real Sociedad. Simeone said on Tuesday that Lookman was still feeling discomfort. If he does not start, Atletico lose one of their most incisive attacking options.

Atletico have never lost a Champions League knockout match to an English team at either the Metropolitano or the old Vicente Calderon. Across six such games against six different clubs, they have won three and drawn three. The Metropolitano crowd will be ferocious, fuelled by the fact that the Champions League is Atletico's last remaining shot at silverware this season.

For Arsenal, a draw in Madrid is not a disaster. It brings the tie back to the Emirates, where the atmosphere on a European night can carry this team over the line. But settling for a draw should not be the plan. Their defensive record in Europe this season says there are goals to be had, and if Saka is fit enough to start alongside Gyokeres and Eze, we have the quality to exploit them.

We have lost just one of our last 11 Champions League away matches, conceded only five goals in 12 European games this season and kept eight clean sheets. We are the only unbeaten team left in the competition. Those numbers reflect a squad that knows how to manage the biggest occasions, even when circumstances are against us.

The narrative around our season has shifted. A month ago we were chasing an unprecedented quadruple. The Carabao Cup final defeat to City and the FA Cup quarter-final exit to Southampton changed the conversation. Three defeats in five matches gave the pundits exactly the ammunition they wanted to write us off. City overtook us briefly before we clawed back to the top with that scrappy 1-0 over Newcastle on Saturday. This is the moment where the mentality of the group defines the season. We are tired, we are short of bodies, and we are juggling the most demanding fixture schedule of any team left in European competition.

Simeone knows that. His entire approach will be built around testing our physical limits and waiting for a lapse in concentration. Arteta has to find a way to keep this squad sharp across four weeks of relentless football. That means trusting players like Christian Norgaard, Cristhian Mosquera, and Leandro Trossard to deliver in high-pressure moments. It means managing Saka's workload across the two legs rather than burning him in the first. It means accepting that perfection is not available right now, and that grinding results from difficult positions is what wins trophies in May. We have been in consecutive Champions League semi-finals for the first time in 140 years of this football club. That is not the moment to flinch.