It was the night when Arsenal made their first big statement of the season in the Champions League, when they advertised their desire to go all the way in Europe’s most glamorous competition; to create club history. They had welcomed Atlético Madrid in the third round of league phase matches and it turned into a showcase for all of the best bits about Mikel Arteta’s team.

The bolted door defence. The furious counterpress. The physicality. The speed and ruthlessness. The set-piece productivity. And, linked to everything but trumping the lot, the total self-belief. Arsenal were unable to find a way through in the first half or the early part of the second – it was tight – but they did not panic because they knew the goal would come. It was inevitable. They were inevitable.

When Gabriel Magalhães scored it in the 57th minute, it was the prompt for a devastating salvo, Arsenal raining in three more by the 70th minute. The game would finish 4-0, Atlético departing battered and bruised. It was late October and the performance and result were very much of a piece with the Arsenal of the first half of the season.

As they prepare for the rematch in the Champions League semi-final, the first leg here at the Metropolitano on Wednesday night, it is possible to wonder where that team has gone. The slaying of Atlético feels like a long time ago. Where there was conviction, there is anxiety, especially among the fans. Where there was cut and thrust, there are blockages.

The headline statistic since 22 March, when Arsenal lost the Carabao Cup final to Manchester City, is that they have scored five goals in seven games. The team have laboured to get up and through their opponents and even the defence has looked wobbly at times. When Atlético came to town, there was less fatigue and a good deal less pressure. The situation has changed overwhelmingly.

At the heart of everything is the obsession with winning the Premier League for the first time in 22 years after the runners-up finishes of the past three seasons; the fear of blowing it or, as is frequently said, bottling it.

Those kind of taunts were unfair in their races to the line with City in 2023 and 2024. In the first season, Arsenal overperformed, they were ahead of their curves and they were up against one of the all-time great teams. In the second, they won 16 and drew one of their final 18 league matches. This was not a squad that lacked fortitude.

It would be different this time in yet another fight with City because Arsenal are better equipped in terms of squad depth; they are more experienced. And, just as importantly, this is not a generational City team. It has felt as if it is there for Arsenal to take and so the stumbles have been magnified.

It has led to strange things happening. Such as the Emirates crowd booing the team after the defeat against Bournemouth earlier this month. At that point, they were nine points clear at the top, albeit having played two extra games.

The narrow win over Newcastle last Saturday featured little football and an incredible amount of nervousness. Weirdly, there was greater unease in victory than there had been after the league defeat at City the previous weekend. It was because Arsenal had played at the Etihad, they created. There was possibility. In the grinding, draining 1-0 against Newcastle, in which the prospect of disaster was ever present, there was not as much to get behind and, consequently, more negative emotions, more to worry about.

The situation has bled into the Champions League. When Arsenal drew 0-0 at home to Sporting in the second leg of the quarter-final for a 1-0 aggregate win, there was no great celebratory mood. Some supporters were more concerned with what kind of tone the performance had set for the league fixture at City four days later. Also, how two gruelling ties against Atlético could affect the league campaign.

Arteta was visibly irritated, commenting that it was as if his team were struggling “in the bottom three” of the league, when in fact they were on the brink of perhaps their finest season. It is not as if Arsenal are serial competitors at the business end of the Champions League. They are into their fourth semi-final and they have reached the final only once – when they lost to Barcelona in 2006.

Arteta wants acknowledgment of a rare level of achievement in the Champions League – the 100% record in the league phase; how Arsenal took the scalps of Bayern Munich and Inter, not to mention Atlético. It deserves to stand alone. How can it possibly be viewed as secondary? And the opportunity now is tantalising, not least because Arsenal are plainly in the more favourable half of the draw.

Atlético have been up and down this season and their recent form has been more down than up. When they beat Athletic Club on Saturday, it snapped a four-game losing streak in La Liga and they lost the Copa del Rey final on penalties to Real Sociedad the previous Saturday. In among it all, there was the Champions League quarter-final win over Barcelona. Atlético are brilliant on their day, richly entertaining and the fit-again superstar Julián Alvarez will pose an obvious threat up front. They are not without vulnerabilities.

Arteta is cheered by the return of his own superstar, Bukayo Saka, to fitness. And if Kai Havertz, who sustained a muscle injury against Newcastle, will be missed, then at least Eberechi Eze is in the squad after his precautionary substitution.

The stakes are dizzyingly high and at the back of Arsenal minds will be how close they came in last season’s semi-final against Paris Saint-Germain, the regrets centring upon the miss by the otherwise excellent Saka in the 80th minute of the second leg that would have cut the aggregate deficit to a single goal.

Despite everything, it remains within Arsenal’s power to go one step further. Another dismantling of Atlético feels fanciful. As Arteta knows better than anyone, it is purely about being on the right side of what are likely to be the finest of margins.