It was exciting, physical, full of drama and storylines, and that was before the momentum swung again in this Premier League title match – away from Arsenal just before half-time. Mikel Arteta’s side had recovered from an initial storm in which Erling Haaland put Manchester City ahead with his 100th goal for them – in only his 105th game.

Riccardo Calafiori’s long-range equaliser on his debut for Arsenal was a dream. City were incensed by the morale of a quickly taken free-kick from Thomas Partey earlier in the match and the visitors sensed a chance when Gabriel Magalhães headed them ahead, from a set piece, of course. No team can do as well as Arsenal these days.

Now the boundaries of the game were redrawn once again. We were in the seventh minute of first-half stoppage time and Leandro Trossard, who already had a yellow card, had fouled Bernardo Silva. But what was that? Trossard received the second yellow card for, as it turned out, kicking the ball away.

It was a decision that followed the letter of the law, reminiscent of Declan Rice’s offence when he was booked for a second time in Arsenal’s 1-1 home draw with Brighton at the end of August. This time, however, Trossard was clearly in the game. Arsenal may have been bitten, but they were none the wiser.

So we entered a game with absurdly high stakes between City’s attack and Arsenal’s defence. For the entire second half, Arsenal kept their ten men behind the ball. It was hard to remember how they crossed the halfway line. But they were all about withstanding the pressure. If that involved dark arts – time-wasting, players going down with cramps – so be it.

Could England’s strongest defence protect the narrow lead? Until the end, the answer looked like a yes. Despite City’s territorial dominance, there were only three really big moments and each time David Raya saved. He saved a header from Haaland and two rockets from Josko Gvardiol.

Then came the sting. The extra seven minutes were up when City won a short corner; one substitute, Jack Grealish, set up another, Mateo Kovacic, whose shot was blocked. Another City substitute, John Stones, put the rebound home, saving City and shaping a post-match inquiry that was likely to be long and noisy.

The aggressive tone was set within seconds, with Kai Havertz running into Rodri shortly after kick-off; the City midfielder had to be treated. His team reacted as if they were insulted. Ilkay Gundogan could have scored from a pass from Silva, but then City took control. The first goal felt great when it came and it was a surprise that it came so early. Who the scorer was was unknown.

The move was sparked when Savinho received a ball from Kyle Walker and fired it inside and away from Calafiori. The winger saw space open up between Gabriel and William Saliba – a rare opportunity – and Haaland’s free kick was perfect. Once Haaland got his body in front of Gabriel, the game was set. He didn’t let himself get rattled and shot straight in with the outside of his left foot.

City were unruly, Gundogan slotted a free-kick outside Raya’s post in the 14th minute and Arsenal’s equaliser came like a bolt from the blue. City had lost Rodri; he was blocked again, this time by Partey at a corner, and he appeared to twist his knee.

Tempers flared when Arsenal were awarded a free kick in the middle of the pitch and referee Michael Oliver asked captains Kyle Walker and Bukayo Saka to keep calm. But that didn’t happen.

City were clearly not prepared for Partey’s quick free-kick down the left to Gabriel Martinelli; Walker was out of position. But Oliver let the ball through and the impact was devastating. Martinelli cut back to Calafiori and what a moment it was for the Italian, his curved shot from distance landing in the top corner. Guardiola was furious on the touchline. His players too.

The tide turned suddenly, Arsenal feeling their confidence return. Gabriel headed wide from a corner, unmarked, and after Trossard lifted up from Martinelli’s back pass, Gabriel actually found the net from another corner, outrunning Walker and seeming to want the ball more than any of City’s defenders.

Remarkably, more events occurred before half-time when Trossard was sent off. At first it felt like he had been given a second yellow card for a tackling of Silva’s back, which would have been harsh. His real offence was to punch the ball away as Arsenal prepared to defend the free kick. You could call it a bloodbath. Trossard, who had first been booked for pulling Savinho back, refused to leave the field. Arsenal were stunned, partly because City’s Jérémy Doku had previously escaped a booking for kicking the ball away.

Areta’s team were accused of making a mistake in the 0-0 draw last season. This time it was true. When the second half began, Ben White came on for Saka, the formation was 5-4-0; White at right centre-back, Jurrien Timber alongside. City tried to find a way through and for long stretches it looked as if they had run out of ideas. Arsenal looked secure. Then they were breached.