Mikel Arteta had promised that this week would be the acid test of how much Arsenal have improved this season, and this combative performance suggests they still have a lot of work to do.

But after clearing the first hurdle against Tottenham on Sunday, it took a miraculous double save from David Raya to save them from defeat in the opening game of their Champions League campaign, after their uncoordinated performance only highlighted how much they were missing captain Martin Ødegaard.

Looking back, the Arsenal manager will be happy to return to London with a point after his team were outclassed at times by Atalanta. However, things could have gone even better had Gabriel Martinelli not wasted a great chance to seal the win with 10 minutes left. Arteta had stressed before kick-off that Sunday’s match against Manchester City had had no impact on his team line-up. But Ødegaard’s continued absence led to him selecting Gabriel Jesus as the attacking line-up following his return from a groin injury, while Kai Havertz was asked to provide the creative spark to support the Brazilian striker.

Three defeats in five away games in Europe last season were in stark contrast to their form on home soil, where they won all but one game – the 0-0 draw at City in March. Facing an Atalanta side who enjoyed the greatest European night in their club’s history just 120 days ago when they beat Bayer Leverkusen in the Europa League final was no easy task.

Gian Piero Gasperini’s side may be entering their fourth Champions League season, but in the previous three they picked up points against Manchester City, Manchester United and Liverpool. In a stadium that has just completed a £100 million renovation, the home fans put on a show before kick-off by creating a tifo with the message “freedom of thought“ (free to dream).

Havertz needed just five minutes to make an impact, combining with Bukayo Saka and bursting into the box, but his weak right-footed shot went wide. Saka was much closer when he was pulled back by Éderson and fired the resulting free-kick around the Atalanta wall into the bottom corner.

Marco Carnesecchi did well to reach the ball and the Atalanta goalkeeper reacted quickly to parry Thomas Partey’s follow-up shot. Martinelli shot over after more good build-up play as Arsenal tried to gain the upper hand.

Atalanta initially struggled to get out of their own half, although they looked dangerous whenever Ademola Lookman – deployed here as a No.10 by Gasperini – got the ball. Charles De Ketelaere had the first chance to score for the hosts, but his left-footed shot went wide. A measure of how well they had come into the game after a slow start was the fact that by the 35th minute they had played significantly more passes than Arsenal, even if they had not yet tested Raya.

At the other end, Jesus – starting for the first time since late April – gave the ball away twice just as Arsenal looked ready to counterattack. Arteta looked like a manager with a lot to think about as he walked down the tunnel at half-time.

Arsenal’s players were grouped together just before the start of the second half, but they couldn’t have made a worse start. Partey had just committed a foul on Éderson in the centre circle when he was brought down again by the Brazilian on the edge of his own penalty area.

There was little sign of actual contact, but there was no doubt that Partey had been clumsy in his tackle and referee Clément Turpin immediately pointed to the penalty spot.

While the decision was confirmed by VAR, Raya ran to Arsenal goalkeeping coach Iñaki Caña for advice. Whatever he said, it obviously worked, as the Spanish goalkeeper parried Mateo Retegui’s initial attempt before somehow managing to stop the penalty taker’s follow-up shot with a brilliant goal-line save.

Arteta responded by replacing Partey and Jesus almost immediately with Jorginho and Leandro Trossard, but his side still could not regain control. Instead, it was another substitute, former Chelsea winger Juan Cuadrado, who had the next chance to score, but his long-range shot went just too high.

The Colombian came even closer shortly after, while Raheem Sterling – who became the first Englishman to play for four different clubs in the competition with his late substitution – made an almost immediate impact when he set up Martinelli after a pass from Havertz.

But the Brazilian wasted his luck and shot high and wide, much to the disappointment of the travelling fans behind the goal. Arsenal now go into the showdown with City battered but not yet defeated.