Arsenal 3 Liverpool 4

Jurgen Klopp lost himself in the moment. The Liverpool manager beat his chest and, in the frenzy, he knocked his glasses from his face. Adam Lallana had just put his team 2-1 up early in the second half and, when the passions had cooled, Klopp fished around on the floor in order to reacquaint himself with his lenses.

What followed had Klopp and everyone else inside the Emirates Stadium rubbing their eyes in disbelief. Liverpool were irresistible for a golden period after the interval, which climaxed in Sadio Mane, the £30 million signing from Southampton, fizzing home their fourth goal. Klopp was central to the celebrations on the touchline, allowing Mane to clamber on to his back.

At that point, Liverpool's dreams ran riot. They were marvellously clinical, with their other expensive new boy, Gini Wijnaldum - the £23 million purchase from Newcastle United - also prominent. Then, there was Philippe Coutinho who, not for the first time at this venue, was a joy to watch. He had equalised for 1-1 at the end of the first half with a scintillating 30-yard free-kick while he also scored his team's third goal.

It was some game to open the season in north London but it was enjoyable only for Liverpool, where something feels as though it is stirring under Klopp. He restored belief and unity last season and, after a full pre-season in which to hammer home his high-intensity methods, it is possible to feel the optimism.

For Arsenal, there was bitter frustration and the same old questions, despite their gallant attempt to bounce back up off the canvas after Mane's goal. The substitute, Alex Oxlade-Chamberlain, scored a fine solo goal and when Calum Chambers flicked home a header for 4-3, there were thoughts of the crazy 4-4 draw between the teams at Anfield in 2009.

But an Arsenal equaliser never really looked like materialising and, instead, there was the familiar sound of a chorus of boos at the full-time whistle. Ars?ne Wenger had been without seven players because of fitness issues and his makeshift central defensive pairing of Chambers and the new signing from Bolton Wanderers, Rob Holding, would fail to instil confidence.

After a decent first half, which featured Theo Walcott missing a penalty and opening the scoring with an expert finish, it was shocking to see how they were taken apart and it is now inevitable that the calls for Wenger to reinforce the squad with action on the transfer market will be renewed.

Wenger had chosen to leave his one big-money signing, Granit Xhaka, on the substitutes’ bench until the 67th minute while his decision to start Walcott ahead of Oxlade-Chamberlain on the right had also been a surprise, and not only because the latter had shone in pre-season. Walcott has tested the patience of the Emirates crowd and when he missed his penalty, it might have been the prompt for another trying afternoon.

Instead, he showed his character to fashion the breakthrough. When Alex Iwobi slid the pass over to him, after Francis Coquelin had won possession, and with Alberto Moreno nowhere to be seen, Walcott faced the acid test of nerve. Happily, his instincts took over.

The first touch to control and set himself was true and the finish into the far corner was low and lethal. A sense of relief underpinned the emotional celebrations.

The penalty had been awarded on 28 minutes after Moreno's reckless lunge at Walcott. Did Moreno even need to challenge? There was considerable surprise when Walcott grabbed the ball and insisted upon taking it. Perhaps, he was motivated by the need to make a statement on the opening day. Either way, Simon Mignolet read his intentions and plunged to his right to beat away the kick. It was the first penalty Walcott had taken in 10-and-a-half years as an Arsenal player.

Arsenal were the better team in the first half, and yet Liverpool found the equaliser at the very end of it and what a goal it was - a celebration of Coutinho's technique and accuracy. Holding conceded the free-kick 30 yards from goal after nibbling into the back of Coutinho and the midfielder exacted the full punishment. From the moment that Coutinho worked the ball over the defensive wall, Petr Cech did not look the favourite to save.

Liverpool had previously gone close in the 40th minute when Roberto Firmino and Coutinho worked a quick break, with Arsenal exposed, and Wijnaldum arrived to strike at goal. He went for accuracy with the inside of his right boot when the laces might have been the better option. Cech got across to save. With Mane prominent, the visitors had other flickers before the interval without them leading to anything clear-cut.

Arsenal could point to a couple of early chances for Aaron Ramsey. Alexis Sanchez, playing as the No9, created the first, which Ramsey jabbed at Mignolet and the second followed a loose header from Moreno. Ramsey's first touch was not perfect and Moreno tore across to make the saving tackle.

The way that the tide turned from the 40th minute, when Liverpool had their first clear opening through Wijnaldum, was the major feature of the game and, yet again, it could raise questions about Arsenal’s mental fortitude. It also shone a light on the vibrancy of the team that Klopp is creating.

For a mesmerising period at the beginning of the second half, Arsenal could not lay a glove on their opponents. Liverpool scored three beautifully constructed goals and they might have had another on 59 minutes when Firmino tormented Chambers before crossing for Coutinho, who low shot was kept out by Cech. Lallana was close to converting the rebound.

Liverpool took the lead when Coutinho's wonderful flick released Wijnaldum and his cross found Lallana, whose chest control took him away from the goal before his crisp finish sent the ball pinging past Cech. Wijnaldum was involved in the third, finding Nathaniel Clyne, who fizzed over a low cross that had the panic alarm sounding inside the Arsenal defence. Coutinho nipped in front of Nacho Monreal to touch home.

Liverpool appeared to be staging an in-house goal of the month competition, and Mane’s deserved a few votes. Like Coutinho, he was excellent to watch, all quicksilver movement and electrifying pace, and when he sliced inside, leaving a trail of destruction behind him, he unfurled a rising drive into the far top corner.

Wenger lost Iwobi and Ramsey to what looked like muscular injuries (Klopp would see Coutinho depart later on, too) and yet, the home team rallied. Oxlade-Chamberlain cut inside Lallana and Clyne before beating Jordan Henderson and embarrassing Mignolet with a low shot inside the near post and Chambers rose the highest to glance in the substitute Santi Cazorla's free-kick. It was not enough and it was Liverpool, through Firmino and Henderson, who might have scored towards the very end. Guardian Service