Mikel Arteta promised that this week would be the ultimate test of how much Arsenal have improved this season. Given this lackluster performance, they still have a lot to improve on.

But after clearing their 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, a disjointed display that only served to underscore how much they miss captain Martin Ødegaard.

In hindsight, the Arsenal manager will be pleased to return to London with a point after his side were outclassed at times by Atalanta, although it could have been even better had Gabriel Martinelli not squandered a glorious chance to seal victory with 10 minutes to go. Arteta had insisted before kick-off that Sunday’s clash with Manchester City would not affect his team selection. But Ødegaard’s continued absence meant he selected Gabriel Jesus to spearhead the attack following his return from a groin injury, with Kai Havertz called upon to provide the creative spark in support of the Brazilian striker.

Three defeats in their five away games in Europe last season were a stark contrast to their domestic form abroad, which saw them win all but one – a 0-0 draw at City in March. Playing against an Atalanta team who enjoyed the greatest European night in their history just 120 days ago when they beat Bayer Leverkusen in the Europa League final was never going to be an easy task.

Gian Piero Gasperini’s side may be in their fourth Champions League campaign, but in the previous three seasons they have taken points from Manchester City, Manchester United and Liverpool. In a stadium that has just completed a £100million refurbishment, the home fans put on a show before kick-off by unveiling a tifo with the message “free to listen(free to dream).

It took just five minutes for Havertz to make an impact when he combined with Bukayo Saka and raced into the penalty area, only to send a weak shot wide with his right foot. Saka went much closer when he was pulled back by Éderson and fired the resulting free-kick around the Atalanta wall and into the bottom corner.

Marco Carnesecchi did well to reach it and the Atalanta keeper reacted quickly to keep out Thomas Partey’s follow-up. Martinelli then fired over after more good build-up play as Arsenal looked to establish dominance.

Atalanta initially struggled to get out of their half, although they looked a threat when Ademola Lookman – deployed here as a No. 10 by Gasperini – got the ball. Charles De Ketelaere had the first sight of goal for the hosts, but his left-footed shot went wide. A measure of how they had come into the game after a slow start was the fact that they had completed significantly more passes than Arsenal by the 35th minute, despite not yet testing Raya.

At the other end, Jesus – making his first start since late April – was twice guilty of wasting possession just as Arsenal looked set to launch a counter-attack. Arteta looked like a manager with a lot to think about as he walked down the tunnel at half-time.

Arsenal’s players huddled together as the second half was about to begin, but they couldn’t have made a worse start. Partey had just fouled Ederson in the centre circle when he found himself facing the Brazilian again on the edge of his own penalty area.

There was little actual contact, but it was clear that Partey had been clumsy with his foul. Referee Clément Turpin immediately pointed to the spot.

As the decision was being confirmed by VAR, Raya ran to Arsenal’s goalkeeping coach Iñaki Caña for a consultation. Whatever he said clearly worked, as the Spanish keeper parried Mateo Retegui’s initial effort before somehow saving the penalty taker’s header with a brilliant save on the goal line.

Arteta responded by almost immediately replacing Partey and Jesus with Jorginho and Leandro Trossard, but his team were still unable to regain control. Instead, it was another replacement in former Chelsea winger Juan Cuadrado who had the next chance on goal, but his diving effort from distance was just too high.

The Colombian went even closer shortly afterwards, while Raheem Sterling – who became the first Englishman to play for four different clubs in this competition when he was introduced late in the game – made an almost immediate impact when he set up Martinelli after he had been played through by Havertz.

But the Brazilian misplaced the ball and shot high and wide, much to the disappointment of the travelling supporters behind the goal. Arsenal went into the confrontation with City, but were not defeated.