Alexandre Lacazette scored a beauty, Pierre-Emerick Aubameyang made the points safe and Unai Emery could toast a fourth consecutive Premier League win. Yet this was an afternoon when the margins were fine and the result could just as easily have gone the other way if Everton had turned up with their shooting boots on.

Petr Cech was the star turn and Emery’s decision to persist with the goalkeeper ahead of the summer signing, Bernd Leno, was more than vindicated. Cech made five stops in the first half that ranked from decent to excellent and, more than anyone, it was the 36-year-old who created the platform for victory. He went on to save brilliantly from Michael Keane at 2-0 and again from the substitute, Cenk Tosun, to ensure a first clean sheet of the Emery era. Everton felt chiefly frustration and not only because Aubameyang’s goal that killed the game ought to have been disallowed for offside. It was not even a borderline call. The Arsenal forward was a full yard in front of Jonjoe Kenny, the last defender.

The visitors had been the better team before the break and, on another day and against another goalkeeper, they might have been comfortably in front. The positive aspect for the manager, Marco Silva, was the fluency his players showed and how, initially, they knocked Arsenal from their stride. There was little wrong with his gameplan. The bad news was that it was not the first time Silva’s players had been guilty of profligacy; it was a similar story in the home defeat by West Ham last weekend. Everton have taken six points from their opening six fixtures and this was their 21st defeat in 25 visits to Arsenal. They have drawn the other four.

It was noticeable to see the Emirates Stadium was pockmarked by empty seats, particularly in the middle and upper tiers, and the atmosphere could best be described as subdued for long spells. Nobody quite knows what to make of this Arsenal team yet; they are waiting to judge them.

There was the sense of square pegs in round holes, with Aubameyang shoehorned in on the left and Mesut Özil stationed on the right – and struggling to suppress the urge to drift inside. The natural width must come from the full-backs Héctor Bellerín and Nacho Monreal.

There were times when Arsenal lacked imagination but it would turn out well enough after Lacazette had turned the contest on its head. The irony was that – wonderful finish aside – the centre-forward was peripheral and Emery admitted afterwards he was about to substitute him when he scored. Alex Iwobi was stripped and ready. Everton were more coherent in the first half, more threatening – particularly through Richarlison – while their pressing panicked an Arsenal defence in which Shkodran Mustafi endured a couple of wobbles and Sokratis Papastathopoulos was forced off with a knee injury.

Silva’s team could curse Cech from the second minute, when he made his best save. The Everton captain, Tom Davies, set Dominic Calvert-Lewin clean through but, one-on-one with Cech, the striker could not trick past him. Richarlison – back in the team after suspension – was in the mood. He took a lovely touch, rolled away from Bellerín and extended Cech while he would be denied again by the goalkeeper on 44 minutes. Everton could point to the Lucas Digne free-kick that Cech tipped over and the Gylfi Sigurdsson pass that released Theo Walcott in on goal. Cech was off his line to block.

Arsenal’s only clear first-half chance came in the 12th minute when Aubameyang touched back Bellerín’s lovely cross for Monreal. His connection was not the cleanest but it still required a good stop from Jordan Pickford. Arsenal worked Lacazette into an inviting position on 41 minutes only for him to take a heavy touch while Aubameyang’s overhit cross kissed the top of the crossbar.

Emery gave Lucas Torreira a first Premier League start and the defensive midfielder had some nice moments, although he got himself booked early on when he jumped into a tackle on Sigurdsson.

Silva felt his team started the second half brightly but they would be floored by a one-two punch. There was amazement when Aubameyang’s goal was allowed to stand – he converted from Aaron Ramsey’s flick, which the midfielder executed with his trailing leg after a little stumble. Arsenal had snapped forward through Özil after a mistake by Kurt Zouma.

Lacazette’s opener was marked by the highest class. Arsenal were chuntering over a non-penalty award, after Aubameyang had headed against Kenny’s hand at close quarters, but the moans were overtaken by smiles when Lacazette collected Ramsey’s pass, took a touch to set himself and picked out the far, top corner with his right foot.