It was a performance of two faces by Arsenal on a night when they absolutely had to win; dropping points at relegation-threatened Luton is not a part of any championship portfolio.

For longer than anybody connected to Arsenal will care to remember, it looked like being a tale of their defensive softness. That, and the steel and silk of Luton – all of their players bringing the former; Ross Barkley, the best player on the pitch, contributing the latter. In abundance.

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The man in the firing line for Arsenal was the goalkeeper, David Raya, with Amazon Prime becoming the latest broadcaster to show the obligatory cut-aways to the back-up, Aaron Ramsdale, sitting glumly on the substitutes’ bench. Raya was at fault for the Elijah Adebayo header for 2-2 at the start of the second half, failing to come for a corner with any conviction and just being overpowered by the Luton centre-forward. Yet much worse was to come. When Barkley drilled a low shot at goal, Raya was horribly slow to get down, allowing the ball to fizz underneath him for 3-2.

Luton were buoyant. They had been determined to build on their previous two results at home – the draw against Liverpool and the win over Crystal Palace. Further reward looked on and the question was simple – what did Arsenal have by way of response?

The answer, happily for them, was more attacking menace, more of the cutting edge that had characterised the performance. And they showed it until the very last. Luton thought they had a precious point. Arsenal had pushed after Kai Havertz’s equaliser on the hour but the last of the six additional minutes had been played and still the scores were level.

Enter Declan Rice. It was Martin Ødegaard who whipped over the cross after Arsenal recycled a move with nerveless patience and there was Rice to flick a header into the far corner. Cue bedlam, with Mikel Arteta so overcome by the emotion that he was booked; his third caution of the season, meaning he will be banned from the touchline for Saturday’s trip to Aston Villa.

Yet again, Arsenal had shown their never-say-die belief, making their punches count in the closing stages. They had previously won this season with late goals against the Manchester clubs and Brentford, while they could also count an 84th minute equaliser against Chelsea. This is more like the kind of thing that powers title challenges.

There was never any way that Arteta was going to criticise Raya. He limited himself to saying that his team had to defend better as a group and that was certainly the case on Luton’s first goal for 1-1.

Barkley had served notice of his intention to turn the game into a showcase for his poise and personality on the ball; an early Cruyff turn a highlight. But it was from a corner that Luton cancelled out Gabriel Martinelli’s opener. When they won it, the decibel levels in the stands rose sharply. When Gabriel Osho powered it home, we had lift-off. Martinelli’s marking was weak.

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Arsenal’s first lead of what turned into a thriller had not lasted long. It came when Thomas Kaminski scampered to his left to retrieve a loose Amari’i Bell back-pass and banged the ball out for a throw-in rather than a corner. Gabriel Jesus was quickly on to it and he immediately got Bukayo Saka in behind Alfie Doughty. Saka’s run was typically smart and so was the cutback after the burst. Martinelli’s first-time finish was angled into the far corner.

Arsenal’s responded well to Osho’s goal. Jesus and Martinelli worked Kaminski from tight angles while Saka jinked inside and unfurled a curler for the far corner. The goalkeeper did very well to fingertip it away.

Arsenal deserved their goal before half-time, which again stemmed from a move up the right. Ben White played a give-and-go with Saka; what a lovely return pass it was and how White put it on a plate for Jesus, the cross perfectly floated. Jesus’s unchecked leap was majestic. He could not miss with the header.

Barkley looked like he was playing with his own ball at times. His technical quality shone brightly and it was a lovely pass that he pinged into Andros Townsend after the restart, the winger’s shot deflecting for a corner. Again, Luton’s brought the desire and aggression on it. Raya could not cope. He was bullied by Adebayo, who pushed away Rice and timed his leap.

Barkley’s evening would get even better; Raya’s would deteriorate. Barkley had surged from halfway, carrying up the inside left, revelling in every caress of the ball when he cut across to Townsend and got it back on the left hand side of the area. A step-over, a swerve to the outside, a low blast. Raya felt the ball swoosh underneath him. Arsenal had previously conceded only three away goals in the Premier League all season.

Back they came again. The equaliser was all about the presence of Jesus, who reached a high punt forward by Saka and held off Teden Mengi before picking out Havertz. Jesus was outstanding and so was Saka, the pair shimmering with menace throughout. Havertz had gone close with a header towards the end but it was not a night when Arsenal would fall short.