It was always likely to stand as a barometer for Arsenal as much as anything else. How would they measure up to Paris Saint-Germain, one of the powerhouses of the Champions League? Extremely well, was the answer.

On a night to bolster the collective belief for the bigger challenges ahead, especially those that will surely come after the group phase of this competition finally reaches it climax, Arsenal showed their mettle in the duels and a cut and thrust to delight the home crowd.

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Kai Havertz scored with a towering header and when Bukayo Saka snaked a 35th-minute free-kick through a mass of bodies inside the PSG area and in, past the partially sighted Gianluigi Donnarumma, Arsenal knew it was theirs to lose.

They would survive a few scares towards the end; a PSG goal could have made it interesting. But Arsenal never really looked like losing their control.

There was the sense of too many pretty touches from PSG and not enough bite in the areas that mattered. But the biggest takeaway concerned Arsenal’s strength. It was there on a mental level, Mikel Arteta happy with the maturity of his team, how they remained clear-headed throughout. And particularly in physical terms.

These Arsenal players are imposing, the majority of them standing at six foot or over, and their basic hardness was frequently too much for PSG. Arsenal missed a number of clear chances but it did not matter. It added up to a statement made by them, even if it was difficult to quantify the importance of the result given both clubs will likely advance.

The atmosphere was coloured by the PSG fans, who had bounced as one seething mass before kick-off and did not stop swaying to the beat of their drums. But it was the Arsenal support who could celebrate in the 20th minute and it was because of an old-fashioned move with an old-fashioned finish, Havertz rising high to get to Leandro Trossard’s chipped ball from the inside left before Donnarumma. It was brave from Havertz; he risked harm as Donnarumma brought his hulking frame off the line.

Luis Enrique had made a statement before the game, leaving Ousmane Dembélé out of his PSG squad; the pair clashed after last Friday’s win over Rennes. The manager accused Dembélé, who is probably his highest-profile player, of disrespecting the team and it reinforced the message around the club these days. No more Galácticos. Less ego; more endeavour and unity. That said, it was a move that undoubtedly weakened PSG.

Related: Kai Havertz leads clinical Arsenal to just the kind of of win they need | Barney Ronay

PSG could point to a Nuno Mendes blast that kissed the outside of the far post and an Achraf Hakimi effort that David Raya got up and over his own crossbar. But the first half otherwise belonged to Arsenal. They were determined to show why Luis Enrique had described them as the best team in Europe without the ball.

Riccardo Calafiori and Jurrien Timber won big one-on-ones against Hakimi and Bradley Barcola respectively while Gabriel Magalhães celebrated when he ushered the ball out in front of Warren Zaïre-Emery.

It was really about what Arsenal did in the final third before the interval. Saka had curled wide early on after a pass from Calafiori while Havertz crossed dangerously from the byline, nobody in red making the necessary run. Arsenal turned the screw at 1-0 and it was yet another set piece that gave them the cushion.

PSG stood accused of not doing their homework when Saka whipped over a low free-kick from the right. One by one, Arsenal players attacked the ball, getting in Donnarumma’s eyeline; first Gabriel Martinelli, then Gabriel and Thomas Partey. It simply went all the way through. From a PSG point of view, it was horribly soft and they were thankful it did not get even worse shortly afterwards, Donnarumma blocking at close quarters from Trossard.

PSG wanted Vitinha to dictate from in front of the back four; he had runners either side of him in Zaïre-Emery and João Neves. Vitinha’s appreciation of his angles and options, often in the tightest of spaces, is lovely to watch. More broadly, it was possible to see the strut in PSG but they needed more than decoration.

Arsenal ought to have made it 3-0 early in the second half, with Martinelli and Havertz blowing chances. Martinelli’s was the big one.

It was a lovely one-touch move from right to left, starting with Saka, who was excellent from the outset – so explosive, so direct – and going through Trossard and Havertz. Martinelli was alone only to volley straight at Donnarumma. The goalkeeper would be grateful that Havertz did likewise with a downwards header from Martinelli’s cross.

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Arteta got Mikel Merino on as a substitute for a belated debut, the summer signing having recovered from a shoulder injury and PSG pressed onto the front foot in the closing stages. Arsenal appeared happy to invite them on, to preserve what they had, to back themselves in the challenges. There were nervy moments for them. Neves flicked a corner down and up against the crossbar while Raya parried a little riskily from Lee Kang-in’s curler.

Martinelli would be denied by Donnarumma once again, another clear opening, and PSG knew there was no way back for them when the referee, Slavko Vincic, ignored their penalty appeals after a loose ball reared up and hit Calafiori’s hand. Luis Enrique was incensed but Calafiori did not look to have moved in a deliberate way.