Pep Guardiola had made up his mind. The Manchester City manager had been aware for five or ten minutes, and so when the half-time whistle blew in Wednesday night’s Champions League clash against Inter at the Etihad Stadium, he dashed off to the dressing room, keen to implement his plan. This is a significant aspect of Guardiola’s brilliance. The capacity to recognize when and where things are going wrong; to make the necessary adjustments. On this occasion, not much was going right. City were stifled, unable to find their rhythm or sharpness. There was an unusual sense of vulnerability about them. Inter exuded confidence – except in front of goal. They moved calmly from the back. They surged through City during transitions. Guardiola was particularly concerned when one of his players lost possession without adequate support around him.

Inter’s low 5-3-2 block was stifling, oddly captivating, with players swarming en masse from side to side, forcing City to recycle possession quickly, which they struggled to do. The Inter strikers, Marcus Thuram and Mehdi Taremi, pressured Rodri. City’s midfield orchestrator could not connect the play. This is a challenge Guardiola has faced before and will likely face again – including on Sunday when City host Arsenal in an early-season Premier League title-race showdown. Arsenal parked the bus at the Etihad last season, leaving with a 0-0 draw in March that was very much a point gained. Will they adopt a similar approach? It’s easy to think so, especially with their playmaker Martin Ødegaard injured. Mikel Arteta seemed to prioritize making his Arsenal team hard to beat first and foremost at Tottenham on Sunday, solidity being the foundation for their eventual 1-0 win. And if it worked at Spurs, having done so previously at the Etihad …

There is no doubt Arteta will scrutinize every detail of the Inter performance and draw ideas from it. Guardiola was asked if the Arsenal game would be similar, and he said he didn’t know; it would be up to him to decipher Arteta’s tactics and react. But he added: “It’s another incredible team, they defend really well, they don’t concede chances, they don’t concede goals, they are really good in many aspects, they control everything.” Which, in summary, sounded like a yes.

Guardiola’s response to Inter at half-time illuminated those internal calculations. Kevin De Bruyne sustained an injury in the 44th minute after a collision with the Inter goalkeeper, Yann Sommer, which makes him doubtful for the Arsenal game. But Guardiola would have substituted him regardless, moving Bernardo Silva out of the other central attacking midfield role, repositioning him on the right with Savinho making way. Guardiola wanted his most agile midfielders in that congested area and so Phil Foden and Ilkay Gündogan came on. Rico Lewis was instructed to step up and move inside from right-back.

“We especially needed players in small spaces, who move,” Guardiola said. “Rico, Phil and Gündo are the best we have in that position. In the pocket, the small spaces. The way Inter defended … I was thinking about 35, 40 minutes that I want to make this substitution. After, what happened with Kevin and the doctor said to me he was not ready to play [on]. But I was thinking to change already in half-time.” Guardiola hoped to position Foden where he could spin and shoot or Gündogan to attack the six-yard box, and both scenarios unfolded, though not with the desired outcome. Here, perhaps, lay the biggest takeaway in terms of the Arsenal game.

Foden shot straight at Sommer in the 69th minute after a touch from Gündogan in a crowded area; either side and he would surely have scored. Gündogan missed two headers in stoppage time after getting on the end of crosses as it finished 0-0. In these types of matches, all tactical nuances and maneuvers narrow to a fine point, the margins vanishingly tight. It’s about being decisive. City cannot be blunt on Sunday.

There is a final, related discussion point. Rodri has brought the issue of player burnout to the forefront, suggesting that strike action could be an option as the schedule intensifies, including two extra Champions League group phase ties under the new format. Yet Rodri has started only one game this season; ditto Gündogan, and Foden has made two 45-minute appearances off the bench. Are City prepared in their engine room for such a pivotal test? Arsenal will bring a near-flawless record from their travels during the calendar year; 11 league matches played, 10 wins and a lone draw. It was the one at the Etihad. City want it to be different this time.