Pep Guardiola had made the decision. The Manchester City manager had known for five or 10 minutes and so when the half-time whistle sounded in Wednesday night’s Champions League tie against Inter at the Etihad Stadium, he sprinted off to the dressing room, eager to put the plan in place. It is a major part of Guardiola’s greatness. The ability to see when and where things are going awry; to make the needed changes. Here, there was not much going right. City were blocked up, unable to find fluency or incisiveness. There was an unusual kind of vulnerability about them. Inter oozed assurance – apart from in front of goal. They built calmly from the back. They got up and through City in the transitions. Guardiola worried in particular about when one of his players lost possession without support around him. Inter’s low 5-3-2 block was stifling and strangely captivating at the same time, players rushing en masse from side to side, forcing City to recycle quickly, which they could not do. The Inter strikers, Marcus Thuram and Mehdi Taremi, pressured Rodri. City’s midfield tempo-setter could not join things up. It was a challenge that Guardiola has faced before and will do so again – including on Sunday when City host Arsenal in an early-season Premier League title-race pointer. Arsenal parked the bus at the Etihad last season, emerging with a 0-0 draw in March that was very much on the point gained side of the ledger. Will they adopt a similar approach? It is easy to think they will, especially with their playmaker Martin Ødegaard injured. Mikel Arteta appeared to want his Arsenal team to be hard to beat first and foremost at Tottenham on Sunday, solidity the basis for the eventual 1-0 win. And if it worked at Spurs, having done so previously at the Etihad … There is no doubt Arteta will scrutinise every inch of the Inter performance and take ideas from it. Guardiola was asked whether the Arsenal game stood to be similar and he said he did not know; it would be down to him to read Arteta’s tactics and react. But he added: “It’s another unbelievable 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 shone a light on those internal whirrings. Kevin De Bruyne sustained an injury in the 44th minute in a coming-together with the Inter goalkeeper, Yann Sommer, which has made him a doubt for the Arsenal game. But Guardiola would have withdrawn him regardless and moved Bernardo Silva out of the other central attacking midfield role, repositioning him on the right with Savinho making way. Guardiola wanted his most nimble midfielders in that congested area and so on came Phil Foden and Ilkay Gündogan. Rico Lewis was under orders to step up and inside from right-back. “We especially needed players in small spaces, who move,” Guardiola said. “Rico, Phil and Gündo are the best that 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 get Foden into a position where he could spin and shoot or Gündogan to attack the six-yard box and both scenarios played out, although 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 blew two headers in stoppage time after getting on the end of crosses as it finished 0-0. In these type of matches, all the tactical nuance and manoeuvres narrow to a fine point, the margins vanishingly tight. It is about being decisive. City cannot be blunt on Sunday. There is a final, related discussion topic. Rodri has done plenty to put the issue of player burnout front and centre, saying that strike action could be an option as the schedule thickens, taking in 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 a pair of 45-minute appearances off the bench. Are City ready 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.