Pierre-Emerick Aubameyang netted twice in the closing stages as Arsenal won six consecutive league matches within a single campaign for the first time since 2016. But the second half they scored very easy goals. Eventually, the pressure paid off, as the youngster used the space he had been left in to surge forward before passing to Nacho Monreal on the overlap.
In the 29th minute, Alexandre Lacazette gave a 1-0 lead to the visitors after a composed finished at the near post.
Just three minutes later, there was almost a repeat, as Iwobi found himself in space again before giving the ball to Welbeck, who played it into the danger area.
Arsenal, perhaps after blowing off some Europa League cobwebs, began to enjoy more of the ball and only a ideal sliding challenge from Maxime Le Marchand prevented Lacazette tapping in Danny Welbeck's cross.
Aubameyang sealed Arsenal's comfortable victory with two of his own 12 minutes later, as he capitalised on Hector Bellerin's assist in the 79th minute. He capitalised on an incomplete clearance and launched a stinging shot at goal from just inside the box, but Bettinelli denied him with a magnificent diving save.
Monreal clipped his cross into Lacazette and the French striker left Tim Ream flat-footed with a nimble turn and close-range strike for his fourth goal of the season.
"It was an important goal for Aaron and an important goal for us", said manager Unai Emery with more than a touch of understatement.
The ball made its way to fellow substitute Aubameyang, who swept the ball across the face of the Fulham goal for Ramsey to flick past Bettinelli.
But moments later, the German made no mistake as he lobbed the ball over Bernd Leno, having been put through by Luciano Vietto's delicate through ball.
Emery's side turned on the style on the banks of the River Thames, romping to their biggest win of the season as the resurgent Gunners moved into the Premier League's top four.